Can I play these NTSC games on my PAL PS2 if I write them to cd? Do I need a special cable (RGB?)? Or is it better to use NTSC -> PAL patches?
ANSWER: BLAZE Scart cable is what you should use. Then no patching if you use CloneCD to copy CD games and you have a fully compatible burner. (See ####://www.elby.com)

And what are these EA patches? Do I need them?
ANSWER: Not if you use CloneCD to copy the CD games

And how do I boot those games, do I need Gameshark or something?
I've read some faqs and some sites, but these things arent really clear to me yet.
ANSWER: It's very clear at ####://www.psxcopyworld.co.uk and ####://www.chipzone.com/ps2booting.cfm
DVD Region X is the simplest booting method