Hello everybody!!!
I am sorry if my question is silly and not at the right place.
I know it's possible to write a script (in any programming language) that would check some webpage every 20 minutes, record its HTML code (source) and store it in some file. I also it's also possible to run it from my computer.
But what if I can't keep my computer on all the time? Do you think it's possible to upload this script to some free web server and run it from there all the time?
Sure, it's possible. You just need to find yourself an outfit that will loan you a server for such a task.
You could go with Google App Engine http://code.google.com/appengine/ if you program in Python or Java. They will let you sign up for a free Web installation. In fact, you can have up to 10 sites.
There are no files there, though. You'll have to learn to work with their slightly quirky database.
There is a facility for running jobs at regular intervals. What runs needs to be a Web service of yours, though; a simple script won't do.
Finally, you'll have to write a Web service that will let you remotely query the results. It's all Web services :)