So you need a lot more than 100 samples per second.
Still, there are lots to choose from, and plenty of MCU's with built-in ADC's that would be fast enough.
How about the ADC0820 from Maxim: 8-bit flash ADC, tristate 8-bit databus with the usual control signals, up to 400ksps, 5V power and unipolar 5V input, you can use the 5V for the reference as well to keep thins simple, and it's inexpensive. Just amplify/divide your signal to 5V full scale.
**broken link removed**