At iChat 2 (Around 2004) there was a beta version before the release of the next OS version (Jaguar)
That is to say the beta was pre Jaguar.
This ran until Apple then release a paid for version when the Beta then timed out.
However the Jaguar release had iChat 2 (Or iChat AV as it was called) as an included free App.
As iChat has been free since then and Messages is to be included in Mountain Lion I would guess that the beta will be Time Limited as well.
Please, if posting Logs, do not post any Log info after the line "Binary Images for iChat"
iMac 2.5Ghz 5i 2011 (Lion 10.7.2)
G4/1GhzDual MDD (Leopard 10.5.8)
MacBookPro 2Gb (Snow Leopard 10.6.8)
Mac OS X (10.6.8),
"Limit the Logs to the Bits above Binary Images." No, Seriously