In Reply To #4
Case Mod (if you don't have a Slim).
Boot Disc = Swap Magic
It's as Clara said, basically.
EDIT
To clarify, you can buy a cheap case mod and install it yourself. What it is, the 'top' of the PS2 casted into a similar shape, but with a flip top. It's still a mod, even though it's not a 'chip' mod. I think it's 30 to 50 bucks. What they did was they casted a shape similar to the top of the PS2 and put a lid on it and a hinge. You'd basically be swapping your top with the new top.
One type of boot disc that exists is called "Swap Magic". It's used for Ps2 games. There's a DVD version and a CD version, buying SwapMagic gives you both.
For PS1 games, you buy a "Breaker Pro" disc, which is the same thing but works only for Ps1 games.
These bootdiscs allow you to play different regions and different formats (PAL, NTSC), but your TV must support that format as well for it to play. Japan games use NTSC which is the same as US games, so the format isn't the problem, it's just the region... which is solved via SwapMagic for Ps2 games.