The new PSP Go was just released half an hour ago at E3 2009, although it was leaked a week ago in Qore.
It features a slider screen, free wi-fi, a new slimmer design, 16 GBs of storage space built in, and no more UMDs! That's right, the new PSP Go doesn't use UMDs, instead you download full games onto your system.
You can also use Duo Memory Sticks just like before, so you could have up to 32 GBs of total storage space on your PSP Go!
The PSP Go is to be released on October 1st, but if you went to E3 you can test it out as I write this!
If you already have a PSP i Wouldn't waste your money for it. the PSP 3000 is just as good. I already have that so I won't get one. Plus THe controls are really close so it feels weird. ANd you can play the same games so really just get a PSP 3000.