Analog input/Digital output for computers

Hello, I'm looking for some way I can get an analog input into laptop/desktop computer.. Most common use will be for temperature control, but I'd like to be able to do other things as well... I'm an intermediate VB programmer, and would need to be able to access the data from the device via VB, and for output, I can always use the parallel port for several digital inputs and outputs if I had to... I'd just need to build a breakout box with some higher power transistors and relays.

I'm sure something like what I need is out there (even USB powered is fine), I just don't know where to look...   I was lookign in the digikey catalog about some ADC controllers with the evaluation boards (One was a 12 channel  12bit via serial, can't remember the number though) but don't have the tools I would need to access it via a PC

Any suggestions?