What sort of account were you using in iChat ?
If was an AIM name you can visit the AIM Site and try to login and follow the "forgotten Password" link to recover it.
The same can be done for an Apple ID (@mac.com, @me.com and @icloud.com are valid AIM names)
If it was GoogleTalk, Facebook or another Jabber server you will have to use their sites for password recovery.
iMac 2.5Ghz 5i 2011 (Mountain Lion 10.8.3)
G4/1GhzDual MDD (Leopard 10.5.8)
MacBookPro 2Gb (Snow Leopard 10.6.8)
Mac OS X (10.6.8),
Couple of iPhones and an iPad
"Limit the Logs to the Bits above Binary Images." No, Seriously