Let me guess - you want to play Silent Hill 4?
Well, I hear there's a flip top solution for your PS2, plus a modchip and a boot disc but some of these including shipping, service and the chip itself might amount of quite a bit.
Buying a Japanese PS2 is a good solution. An alternate solution is a Korean PS2 which is a Japanese PS2 with a different voltage level (converter needed). But at Play-Asia.com they're pretty cheap.