I would guess that almost all the reptile photos on this site were taken with digital cameras. Basic digital cameras have a feature that basic film cameras don't....macro.
Basically, when in macro mode, the camera can focus while it's very close to the subject...which makes for very nice close-up pics of small critters.
There are plenty of good deals on digital cameras these days. Look for one that has macro mode, (most do).
If you just plan on posting your pics on the web and maybe making regular sized prints...3 MP will be plenty of resolution.
I would suggest a camera from either Canon or Nikon. Olympus & Minolta are good too.
Check out
www.dpreview.com for comparisons & pictures of just about any digital camera.