lots of codes
Invincibility:
846754623771FACD
Always have 99 rings:
29F860CEFE350599
Never Lose Rings:
EA2E1E0B8FCE0633
Inf. Lives:
87FD68FBE946B427
..
GameShark Code for Sonic Advance 2
Invincibility:
846754623771FACD
Always have 99 rings:
29F860CEFE350599
Never Lose Rings:
EA2E1E0B8FCE0633
Inf. Lives:
87FD68FBE94..
Invincibility
846754623771FACD