The guys over at psp 3d.com have requested that someone make a mem dump using the GTA exploit on a v2.5 PSP. Seems they're waiting still. Check out the link below for instructions etc, you'll need 2.5, GTA:VCS and ~30megs on your stick.
http://psp 3d.com/showthread.php?t=895 (remove the space between psp and 3d)
EDIT: ...and why is "psp 3d" (without the space) censored?