What are patches? How do we use them?
 

Please advice. Also can a PAL game be converted to play in the USA?

u'll find excellent tutorials and FAQ's here:
www.psxcopyworld.co.uk

Patches can reduce the size of games or change the video from Pal to NTSC for examples. Patches can be found here: http://www.megagames.com/ps2/ps2_patches.shtml and you use ppf-o-matic to apply them to your backup, found here: http://www.megagames.com/ps2/ps2_ppf.shtml