Your PAL TV needs to be able to play 60Hz RGB (i.e. be NTSC compatible). The you need either the red/white/yellow lead or the special Blaze PS2 RGB lead 21 pin SCART for NTSC to play properly.
If your TV is olde ror cheap, then ypucan buy an NTSC to PAL convertor. The best is at
www.maplin.co.uk; the cheapest is at
www.lik-sang.com
I have a Maplin convertor.