I thought I posted this last night but can't find it. Oh well, another senior moment. I will kick myself when someone tells me how simple this is to do.
You can't delete pre-loaded items, items with a gold padlock next to them. But, for items that you've created / loaded on your device, go to Media, find said item, press menu, then delete...
Hi, actually there are ways of getting rid of the preloaded files, but it involves reinstalling the OS. basically you delete all the relevant media files in the folder (program files> common files> Research in Motion> Shared> Java) before doing the install. You'll need an updated OS, or flash and reinstall the OS(the 1st option recommended) in order to do this. There are several sites with detailed info, have tried and successfully did it with my Blackberry Curve. Hope this was of some help.