What probably happened was you hit the shift key during start up. In 10.6 when entering Safe Boot you now receive a progress indicator.
You may have just had something on the keyboard without noticing (like a book), I've done it a few times.
Check out:
Safe Boot takes longer than normal startup
http://support.apple.com/kb/TS1884
Mac OS X: Starting up in Safe Mode
http://support.apple.com/kb/HT1455
Can't find anything on 10.6 yet but to test it out you can hold shift as your machine restarts, it does no harm. Once its booted in safe boot simple restart again without holding anything to go back to normal.
The extract from your log would seem to indicated a safe boot as it referenced the FSCK which is performed in the background during a Safe Boot.