I have seen many schematics for an h-bridge circuit, but they are all very different. I saw some people using only NPNs, some only PNPs, and some both. This one that I found on instructables uses only NPNs.
I notice they used a button and resistors. I am guessing the resistors are to bring the 9v down to a voltage the base of the transistor can handle. Can I get rid of the resistor and use it with an arduino?
Can you draw a schematic?
What are your load?
What voltage do you have to your H-bridge?
You MUST have resistors to the transistors base. In most cases.
If you use 4 NPN and 2 PNP you can use higher voltage than 5 volt ( up to 500 volts or so)
I am still very new to electronics, so I am probably going to say something that does not make sense.
Anyway, my load is going to be a single motor who's direction I want to change when the arduino tells it to.
I am using 6v for these motors and using the arduino's 5v to trigger the base.
I am using this schematic except I am replacing the buttons with the arduino and I guess I have to have the resistors, but if I didn't have to, I would not have those in there.
That schematic did not upload very well.
Here is a link: http://cdn.instructables.com/FVM/W79V/FYYNDQJ9/FVMW79VFYYNDQJ9.LARGE.jpg
I am guessing the resistors are to bring the 9v down to a voltage the base of the transistor can handle.
You guessed wrong. Resistors do not bring down voltage, they just limit current.
my load is going to be a single motor who's direction I want to change when the arduino tells it to.
You need a H-bridge and that thing you posted is not a schematic, it is a physical layout diagram and is quite useless for evaluating all but the most trivial circuits.
There was no schematic posted for this.
Do I need a resistor though?
I don't have that particular resistor with me, so I would have to buy it if I MUST have it in my circuit.
It's not a schematic it's a wiring drawing.
When the current direction is reversed, to avoid short-circuit H-Bridge requests a dead zone.
Because you wrote :
I am still very new to electronics
I think it is best for you to use an integrated Circuit like L298.
I've got doubts that the instructable h-bridge would actually work. If it did work one would see that design being widely used. Some of the comments on the h-bridge indicate that it doesn't work.
Do I need a resistor though?
Yes why on earth do you think anyone would put in a resistor when it was not needed?
I am still very new to electronics
The one important thing to remember is that most things on Instructiables are crap.
This circuit is no exception. Some one traced it out in a crap sort of way but still enough to see how poor the circuit is.
http://tinypic.com/view.php?pic=34t95ia&s=6#.U_jBVEhZUXE
The top transistor, the one connected to 9V is in the emitter follower mode. This means that the maximum voltage you can get on the top of the motor is 4.3V. Couple that with the saturation voltage on the lower transistor and the maximum voltage that circuit can delver to the motor is 3.6V. So if your motor will run of that and give you enough power fine. Otherwise just buy an H-bridge in an IC, it is much cheaper and it will work and it will not flatten your battery or melt things when those two buttons are pushed at the same time.
Grumpy_Mike:
I am still very new to electronics
The one important thing to remember is that most things on Instructables are crap.
+1 
Well the clutter on the site is shocking, its the worst of the commercial web,
And this particular circuit is a bad circuit, avoid.
With low voltage H-bridges you have several options:
NPN + PNP bipolar
n-channel and p-channel MOSFET
An H-bridge chip (preferably not darlington based).
relay H-bridge (no PWM possible, only forward/reverse)
For higher voltages the options include darlington drivers
since the 2.5V overhead is less wasteful at 24V or 48V.
Its less sensible to use NPN/PNP and n-channel/p-channel
bridges at higher voltages as the driving is complex (more complex
than the bridge!).
n-channel only MOSFET H-bridges with high/low MOSFET driver chips
come into their own for high current / high power bridges upto 100V or so.
The MOSFET drivers bootstrap the gate driver supply automatically. Such
bridges have the nice property that the motor supply and driver supply are
independent, either can be powered up or down without having to worry
about back-powering or anything like that.
higher voltages and IGBTs start to take over as they handle high voltage
transients more robustly than MOSFETs