Over at http://blogs.isaserver.org/shinder/2006/05/30/owa-site-appears-garbled-and-mailbox-stuck-on-loading/ I discussed a problem I had with the OWA pages not loading correctly and looking something like this:
Microsoft now has a KB article discussing this issue that you can find at: http://support.microsoft.com/?kbid=910119
HTH,
Tom