Webcam help

PLS reply to mchenney @ mindspring.com

I want to use a wide angle webcam (?) in a mobile application to record
640 x 480 data at 15 -30 frames per second, for days at a time ( target
is 7 days, but only when there is a certain level of motion. The
recording will be a round file type where there is always the latest
data, oldest being erased. Would also like to include voice audio.

Plan was to use Webcam + Laptop ( 100G HD ) over USB 2 or maybe
Firewire. Also want to keep the equipment cost =<< $ 2,000.00

Questions and looking for recommendations:


In future or maybe now would include time / date / GPS and vehicle bus
operational data on periodic frames or in parallel files, as data changes.

USB or Firewire?

How fast or recomended processor / laptop?

Any software recommendations?

Alternate solutions?

Thanks

Dennis