W3SVC Log Files are Filling Up Your SBS's System Drive
I can't believe that I haven't encountered this sooner: The system drive on an SBS 2003 was full. I used my trusty SequoiaView and found that the W3SVC1 folder was 6.14GB - OUCH! A quick Google search yielded an excellent discussion of how to deal with the matter.
At a command prompt enter this all on one line:
at 12:00 /EVERY:Su Forfiles.exe -p C:\WINDOWS\system32\LogFiles\W3SVC1 -m *.log -d -30 -c "Cmd.exe /C del @path\"
This will schedule a job that will run every Sunday and remove W3SVC1 log files that are >30 days old.