Backing up PS2 games... Little help...!!

hi all,
am new to the whole backing up of ps2 games...just wondering if the average size of a ps2 game is around 4gb (like a lot of the ones you see to d/l off the net) or the same as a normal blank dvd, or are they bigger than that and need to be thinned out to fit on a dvd...?
like if i got a game i want to back up, is it the same as backing up a movie...? can i use dvd x copy or do i need something like dvd decrypter....?
cheers,
dave.

basically yes, but you need a mod chip or smiler tool to play backups.

yeh my mate is getting his ps2 chipped tomorrow...