The best web service to get satellites is Heavens-above, however, I'm not sure how you could get their database by yourself.
Aside from that, there are a few options:
- You can download TLEs (Basically, the data required to calulate satellite positions) from Celestrack, and find a library to calculate the satellites overhead from your position.
- You can get the GPS coordinates from a web service easily enough. See this question.