The PSP scene is still kicking despite the Vita being out. Coldbird and co. are constantly working on improving their PRO Online Client that was first released a week ago.
The PRO Client allows you to play adhoc games via infrastructure on the Prometheus' server in a manner similar to Xlink Kai. It functions as an addon to those already on the 6.xx PRO custom firmwares and for those rocking a PSP Slim or newer.
To get you up to speed, the client now has an online menu, keyphrase chat support, a key binding that exits you to the XMB, offline Adhoc Mode and support for Tekken 6. To date, the client supports 12 titles:
•Blood Bowl
•God Eater
•Gods Eater Burst
•Mod Nation Racers
•Pangya Fantasy Golf
•Split Second Velocity
•Tekken 6
•Untold Legends – Brotherhood of the Blade
•Untold Legends – The Warriors Code
•Virtua Tennis 3
•Worms Battle Islands
•Worms Open Warfare 2
With the plug being pulled on official servers, this definitely will prolong the life of these games. If you aren't already the client, you can grab everything you need below.