Firmware 3.90 now available on Network Update
Ready for Skype? Here it is! Get it by accessing Network Update on your PSP. Here are the official details:
Support for PLAYSTATION Network titles has been expanded.
Skype has been added as a feature under Network.* (Only for PSP-2000 series.)
For more details on Skype and their free and paid calling services, visit the Skype official website. Note: Skype requires a PSP headset with remote control.
[Thanks, Jorge H.!]