Team ProjectXX, who where working on a PSP exploit for all models, including PSPgo, seem to have been forced to release their exploit early, due to a leak, all information on that can be viewed in the readme, the exploit needs Splinter Cell Essentials to work.
As stated, this does work with the PSPgo, but Sony will probably end that quick, so try and download the game for your PSPgo, before its pulled of the store.
How to do the exploit:
Set your system language to english,
Put the folder ULES002810int into /PSP/SAVEDATA and h.bin in the root of your ms,
Then run Splinter Cell Essentials and load the save,then press “Continue”,
After a bit you will see a nice Hello World.
All credits goes to:
and special thanks to: