Here are some cool links!

Big Sonic fansites

Sonic Retro (check out their info section!)

the Sonic Stadium

Sonic HQ

Sonic Center

Sonic Blast forums

The rest will be cataloged soon

info.sonicretro.org

tcrf.net A good resource for cut content in games.

Great website you should check out!

an old Sonic fansite

Old Chao fansite