[2005] Check for program updates?

Just wondering, lots of programs have the function that on load, it will automatically check for updates and notify you if there is a newer version out! How can I do this?

Cheers!

They usually check for the setup file over the Internet, if the file's creation time is newer than it's own, it knows there is a new version [that's just one way].
[Another way] you might publish versions table (DB) to the public and check from the client app using a web-service

hmm, i see! but how would i proceed if i want to check the file creation time?

Code example?

Cheers!