i searched the net for some apps...downloaded them into my pc...

but when i connected my 9500 to my pc and tried to load them into my pc via BB desktop manager, it failed to even add to the list..

wrong kind of file? what is the file format for applications for BB 9500?

Typically, applications come in one of two forms.

.jad - installed OTA(Over The Air) - must use blackberry browser to install from a website
.alx - installed via Desktop Manager after downloading to a PC.

Either way, the application must be specifically designed for the model blackberry you are using.