Came back to my mac after several hrs and iPhoto was open and there was an error on screen about low disk space. Tracked it down to the console.log file in library/logs/console/501/console.log. What is going on here?
99% sure you can delete it without a problem however if the Mac explodes, don't blame me.
I seem to remember other members having the same problem with earlier builds of Tiger and from memory, they deleted it and everything was fine. It just recreated a "normal" sized file.
Maybe put it in the trash for a week and see how things go before actually emptying the trash.