Automated web browser

I'm looking for an automated way to browse dynamic web pages. Specifically, Heavens-above.com will generate a table of ISS, Space shuttle, Iridium flares, etc when you plug in your lat/long. I'd like to automate that so I could be notified when something interesting comes along. Is there a tool that can pull down a web page so you can dissect it under program control?

Thanks,
-d