I really suggest you look at the microcontrollers that have A/D converter built on chip. They are easy ti use and require no extra chips. If you look at the CHIPS link button to the left you can scan the device list and see that there are a number of controllers that have A/D converters like this. Most vendors have a couple of parts. Cygnal has A/D converters on every part they make....8 bits to 12 bits.

Michael Karas