I know I can download games for my psp 2000 via the psn store but :

1) do i need a special memory stick ? (is my original memory stick up to snuff)

2) how much memory do I need? for a game like GTA chinatown wars for example

1) The Memory Stick must be bigger than the size of the download

2) The Store will tell you the size of the game

excellent so the newer downloadable games can be played on older psp - they don't require the flash Hd drive of the psp go or whatever internal memory that system uses.

yep, the memory stick just needs to have the enough size for the game

great, i prefer not to buy any more umd's just in case I upgrade to the psp go one day,

I was thinking of picking up one of these 16mg sticks from BB, they are on sale right now

http://www.bestbuy.ca/catalog/proddetail.asp?logon=&langid=EN&sku_id=0926INGFS10100331&catid=20089

that is not 16mg, that is 16 Gigs. I have 4 Gigs

yep, that was a typo, tx for the help.