Any storage device can be partitioned, however this would not be needed for the PSP. You can simply drag and drop music / pictures into the mem card, or their correct folders and it will find them.
The PSP supports Flash 6, the most recent flash is flash 8 i believe, which is what youtube etc use. So a standard psp cannot view youtube. However, a custom firmware psp can. This is Sony firmware with the ability to run "home made" games/apps. Tutorials of getting custom firmware can be found from the link in my sig below.
The psp usb port is a mini-usb connection, you will find them on most TomTom sat navs and Kodak digital cameras. Here are some pics to aid you...
http://greatcables.net/categorylarge/27329.jpg
http://boldt.us/2139-1/sony-psp-usb.jpg
The part you dont know about the psp is homebrew. These are the "home made" games/apps i was talking about above which require firmware version 1.50 or custom firmware to run. When you get your psp, i can help you in the downgrading process. If its new it may require buying a "pandora battery" or making your own if you have some technical knowledge.
Homebrew consists of many things, the most popular i would say are emulators. These act as like a virtual console on the psp, so for example you can play N64, SNES, gameboy game on the psp. Visit
QJ.NET - QuickJump Home - PlayStation Portable News - PSP Updates and have a look around.
Hope that helps.
Kev
