Agent,
Yeah, I've actually got an AD623 (a instrumentation Op-Amp) sample on the way which I'll use in the final design, and the LM324 will probably be used as a general amp for other stuff that comes along.
Daniel,
Do you want me to write something general about Op-Amps? I don't feel confident enough to actually teach other people what to do with Op-Amps. I feel like I know just enough to be dangerous. I guess I'll do a write up on how to interface with the MPX2102 pressure sensor, and kind of skimp over the Op-Amp stuff. I wish I knew how to use Eagle to make cool diagrams and such!
-Z-