Go get the update now! Firmware 3.90 offers up Skype, well, that’s the major addition from the update, I have no clue what else it does, but after you have Skype on your PSP you probably won’t care either.
The downsides are as follows, first, you have to have a PSP-2000, aka the PSP Slim. The second is that the little remote that came with that model PSP, yeah, you had better still have it, as its apparently necessary (probably where the microphone is).
Other than that you get the update, plug in the remote and headset, connect to WiFi, make sure there is space on your memory card for the Skype software, and then navigate to the Network menu and select Skype. From there you can either sign in, or create a new account if you don’t already have one, after you do that you just select someone from your contact list and call away.