small laser for a bow?

Are there any fairly small and inexpensive lasers that would work as a "laser site" for a bow? I am thinking about attaching one just to help me learn how far the arrow drops over distance, and to help me line up left/right better. I figure any small laser will work well - something the size of a AAA battery or CR2 would be idea because I could easily attach it to the bow.

I am not looking for a specialty laser used for bows. I am looking for an inexpensive pen light that I could duct tape to it temporarily.

Well since most shots on a bow are not that far away.
I would figure that a cheap small laser from walmart would work for you.

The farthest i might shoot is about 50 mabey 60 yards.

But normaly around 30ish.

But since i dont have a large amount of knowledge on lasers.
You might think different.

dealextreme usually has some pretty cheap lasers ($10-$20), i would recommend a green one because if you do your practice outside, it is much easier to see in daylight than a red one. Also, if you don't have them already, a peep sight and a trigger release will do wonders for your consistency on your bow. I used to get really frustrated using finger tabs and just an iron pin. Whisker bisket style arrow rests can help a lot too. I would definitely make sure the laser is off your bow before you head to the woods to hunt, DNR officers tend to not be very understanding, and most states have outlawed projected laser beams for hunting, unless you are legally blind and require a spotter.

edit: here is a link for their cheap lasers

The angle of your arrow makes a huge difference, as does the position of your hand, any tilt on the bow. A laser sight on a crossbow is logical, but a manual bow has too much going on to make this much of a useful tool. I can see what you're trying to do, but I think you may be about to mislead yourself. You'll also have the challenge of how on earth you columate the laser with your arrow.

A'd really second what SFG2Lman is saying about the peep sight and trigger release - you'll get far more consistency and accuracy from that than you will trying to use a laser. The peep sights are very popular at the archery group - only two have tried lasers and both found them pretty much useless... in fact that's how I got one of my laser pointers.