How do I delete temporary Internet files on my MacBookPro?

You don't have to. OS X does its own cleanups of unneeded temporary files.

Are you really running 10.2.x?

Sometimes the utilities in your Mac won't be able to catch and delete everything - for example temporarily files like attachments downloaded from webmail - or if you're using a browser other than Safari, the cached images can quickly add up to what's eating storage memory.

You can manually go to the Downloads folder in any Finder window and delete the files there. If you're using Chrome or Firefox (or Internet Explorer), there's usually an option to "Clear Browsing Data", just have to find it under the main menu. In Chrome, for example, it's listed under Chrome>Clear Browsing Data> the dialog box allows you to pick and choose whether to clear everything including history and passwords, or just the temporary internet files.

Hope this helps!