a newbie quetion:

i would like to know how can i create a web application that periodically
perform a background task in my web server?
this is because i need the application to auto-retrieve data of another website(others
ppl's website) and automatically update the data into a database in the server(autorun
for mayb every hour...etc).and i can't use scheduled tasks in my server to
do this.
so, how do i start to build the application?
hope you all can help bcoz this is the first time i build a web application
and i have no idea how to start it.
thanx in advance.