I found this at Active Surplus (in Toronto Ontario, Canada).
It seems to be an IR phototransistor. It doesn't appear to be a IR remote receiver as when I hooked it up like this: Testing an IR Sensor | IR Sensor | Adafruit Learning System, all it did was heat up.
I tried to google the markings but I couldn't find anything.
Does anyone know how to connect it up so that I can detect varying intensities of IR from it?
Thanks. 
all it did was heat up
I hope you bought at least two.
Possibly out of an optical smoke detector?
It is almost certainly a receiver for an IR remote. It sounds like when you tested it the connections were not the same as the tutorial. This is not unusual that different packages have diffrent pinouts.
I've bought a few.
Dunno what it's out of. Just want to see if I can get it to work as I hear that this should be more sensitive than an IR photoresistor.
Yes it has a built in amplifier but it needs pulsed IR at the right frequency, which could be any even number between 30 and 42KHz.
sigh I did try the test using different pin configurations, but don't know if I could have burnt it out during any of the tests. I was told that it was a 3V, so I've only been trying with that. If it were a 5V, I guess I wouldn't see anything eh? 
The frequency I tested it with was around 39kHz. I didn't try anything higher or lower. Didn't think that it had to be an even frequency. Do IR remote receivers have a chip on them? I have about 5, some of which I'm pretty sure must be burnt. I'll try opening one up and see what's inside.
Allot of small devices require small amounts of current (uA thru 1mA mostly) to operate so when "poking around" trying to figure out pins, you might consider putting a 1k resistor inline and keeping an eye on current as you probe it. That way a short or reverse power stands much less of a chance of damaging something.
To me they look like Vishay devices with an optional housing.
Look up the TSOP113x, and the TSOP123x - with x being an even number 0 to 8.
Also the tsop312x, TSOP 1738, and TSOP4038
I sure hope your sigh isn't about the help offered here, but because you're stuck.
I can tell you the manufacturer of the device, and you could have known this too.
In your pics, you can see a styled S shape.
This is the style Sharp uses in their brandname/logo.
So that is where you can start.
But you're a lucky guy today, as i happened to stumble upon this sensor today, mounted in a device i was inspecting before it's thrown in the garbage.
I included pictures of it i made after removing it.
And you can see that these are very very much alike the units you have.
So i googled for sharp, ir and 27 and found a few IR recievers with 27 in its name.
The 27 seems to indicate the generation, characters after that gives info about the housing and the frequency used.
This also gave me some info about how to connect it.
And reverse engineering by inspecting the donor confirmed it.
So here you are:
Your reference is picture "IR2", and the left device.
Pins numbered from left to right.
Pin 1: Output
Pin 2: VCC
Pin 3: GND
The metal bracket holding the device is also connected to pin 3: GND.
There is a capacitor of 10µF over pins 2 and 3, confirming these are the power supply.
Pin 1 was lead to the processor on the board it was mounted on.
I can't tell you what voltage these devices i've got are, because the donors are dead (power supply).
So you'll have to use some trial and error to find out for yourself.
You would have to do that anyway as we can't be sure these units are the same even if they look to be this much.
The donors are XSAT CDTV-410 satellite receivers, a product that they made before this French company was taken over by British pace, and vanished.
Maybe you can find out a bit more by trying to find info about the remote for this receiver, as to the frequency.
This is the best you can be helped here, i'm sure.
The rest is up to you, lots of success with it.
Well done MAS3 on tracking that down.
The donors are XSAT CDTV-410 satellite receivers, a product that they made before this French company was taken over by British pace, and vanished.
I used to work for Pace, they took over two French companies, one was Xcom in Grenoble, I visited it several times as at one stage I was working with them, their name was changed to Pace France. The other was Phillips set top box division.
@adrian_h - I sent you a PM, look at the top right hand corner of this page.
MAS3, my sigh is my frustration. I'm currently not very good at electronics. I'm a software developer trying to break into firmware development. I have a high school understanding of electronics (I went to a tech school). I'm starting to read The Art of Electronics 2nd Ed - Horowitz and Hill, but just starting.
I'm thinking that I'm going to have to get some equipment. I used to have a multimeter, but can't find it. I don't have an oscilloscope.
I'm much obliged by all of your help. I just thought that using this instead of a IR photo-resistor would be more sensitive. I've gotten a reflective range of just over a foot (just over 30cm) using that. I was hoping to see if I could get more, somewhere 1.5 and 2 feet.
I'm not sure what you meant by 'Your reference is picture "IR2", and the left device.' Are you stating that this is the orientation when you are talking left and right? Or are you saying something else?
I've been a bit busy this last week so I've not yet gotten back to it. Hopefully I can take another look over the weekend.
Thanks for all the info. Looks like I may need some probing equipment.
I'm referring to the pictures i enclosed.
I uploaded them to this site instead of to some host, but that means they are added to the bottom of the post instead of inside the post like you did.
As you can see, one of them is named "IR2", and both photo's show 2 sensors each.
You can click on the thumbnail to blow it up so you can see it a bit better.
I have reduced the resolution to 2460 x 1640 px, i guess that will do to see enough detail.
So click on the picture named IR2 and take a look at the left sensor visible in that picture.
Left and right or pins 1 to 3 are as shown in that picture.
Thanks for your help MAS3, it's much appreciated.
Does the -1223 have any meaning?
Adrian
Oh and this is definitely a IR remote receiver and not a phototransistor?
There are 2 kinds of texts visible.
First one on the side is stamped in the metal.
On the back is a printed text, that's most likely a date code.
These are different on both sensors i've got, which are definitive IR receivers.
Difference between phototransistor and receiver, is that the receiver also has a built in decoder/demodulator.
So the receiver's output is the pulsetrain containing whatever message that was sent by the remote and suitable to directly feed to a processor.
adrian_h:
Oh and this is definitely a IR remote receiver and not a phototransistor?
Looks like it to me, but anything is possible. I believe that most IR receivers don't even use a phototransistor, but use a photodiode instead. They have all the circuity needed to receive, amplify (AGC) and demodulate (filter 38kHz carrier) the IR signal. That metal frame often has to be grounded if it isn't already connected to the ground pin. It could be open-collector, so you might have to use a pull-up resistor on the output pin to get anything out of it.
