Hi, i recently borrowed my car shout-cast radio remote and tried to use it with an arduino board, but my attempt failed . I was using a 38kHz receiver and some codes for IR i found in the forum. I assumed that remote with different freq cannot be received.
I am looking for suggestion how to proceed. I don't have osciloscope and fancy equipment to determine the remotes specifications thus i don't know what kind of receiver to buy
http://lh4.ggpht.com/_dmTcJhFq3hI/S4LUNPBFc_I/AAAAAAAAAd4/eDyZsFu9BXE/s800/HPIM0567.JPG
check this library from ken shiriff.
the latest version from his github
if you check one of the last posts from ken, he explains how to use arbitrary codes to map any remote.
I assumed that remote with different freq cannot be received.
Yes: if everything is working correctly, the remote will only trigger receivers that have the same frequency. Or really cheap/primitive receivers that don't have any filtering.
I have some odd remotes, too, so I bought some really cheap (about a dollar each) surplus receivers of different frequencies. That way, I can wire up a test setup with multiple receivers so I can just point the remote at the box, and see which one lights up.
I don't know what the surplus electronics market is like in Bulgaria, but, if you can't find a place like Goldmine, the receivers only have a few pins, so they should be easy to scrounge from broken consumer equipment.
i have a receiver without filtering, but he is trigered from all light sources and the output is constantly blinking
Comet.bg has 38 and 40 KHz receivers.
Search for: RPM7138, RPM7140
the main question remains will 38Khz receiver decode the codes from the remote. i didnt quite understand that example that Davide posted . But perhaps if someone clarify what technique is used it will be good 
The schematics in the example is pretty simple. So you can easily duplicate it. Buying both the 38 and 40 Khz receivers will set you back with less than 1 euro. It's a matter of trying it.
Here is some more info about IR remotes:
I've found that it doesn't really matter if you use a 38kHz receiver with a 40kHz signal or vice versa. You probably lose some range for detection, but it still works. So don't sweat over what receiver to get.