Can you download and play PSP games without a PS3?

I've found a download site PSPAdder and they say you can download PSP games and burn them to CD or DVD or put them on Ipod or PSP. I want it on my PSP. When I wanted to download this game from the Sony Playstation Store, they said I needed a PS3 to activate the PSP game on my handheld. If I download from PSPAdder, will I need a PS3 to activate the game or will it play without it? I ask because I do not have a PS3. Thanks for any help you can provide! It is appreciated!