I dont know a forum but I own 2x PSP's (Geek)
If you plug it in via USB and the computer does not pick it up goto Control Pannel and search for new hardware.
The PSP's now should auto intsall the software.
Make sure when you connect the PSP that the power is ON on the PSP.
Once its available on your explorer you can go into it and put songs etc on it. Please note that it can only play limited Movies due to file type.
Try the official PSP site for more information or possibly a forum.
Good Luck