Anyone using WSUS should take a look at this article, even if you have WSUS installed on a dedicated server you might not want all this logging filling up your volume or you may want to change the default location the logs are saved to.

http://theessentialexchange.com/blogs/michael/archive/2010/01/11/disabling-wsus-logging-or-any-website-on-windows-server-2008.aspx