It's an app you can download through a PS3 that allows you to play ad-hoc only games over the internet. From what it says in your signature, you already have a PS3. Ad-hoc party can be downloaded from PSN for free, so you should have no problem doing this, as long as your PS3 is connected to the internet with an ethernet cable (ad-hoc party doesn't work with wi-fi). Look in
this thread for more information.