Calculating resistance for driving motors off Arduino
Power is not a problem, since the H-bridge won't force the motors to actually use all that it is capable of putting out.  It can put out up to 1 Ampere of current, but the motor doesn't have to draw that much.

What might be a problem is that the H-Bridge can only work with a power supply starting at 4.5Volts for the motors.  However, if you look at the specs, you will see that it only delivers about 3Volts of the 4.5 to the motor - so, you are good to go if you can provide 4.5Volts to the VCC2 input (pin 8) of that chip.  If you use 5Volts, you will probably be OK.

Use the H-Bridge as is, no additional resistors in series with the motors.  Provide 5V (or better, 4.5) to Pin 8 from a supply that can deliver enough current for two motors.  Avoid powering the H-Bridge from the same supply as your Arduino, or provide plenty of bypassing (capacitors on the 5Volt supply to the Arduino) to filter out the noise.



I see Andy aka checked the specs on the motors.  Yikes! That is too much current for that H-Bridge, so don't use that one.  Sparkfun also supplies chips that can handle upto 4A, as well as finished modules using those chips.