If you see this error:
Request Entity Too Large. The requested resource /kb/index does not allow request data with GET requests, or the amount of data provided in the request exceeds the capacity limit. Apache/1.3.33 Server at support.apple.com Port 80.
When looking at Apple's site the ONLY fix for me (other than relaunching Safari) is to delete every single Apple cookie in Safari. I don't have the patience to delete one at a time and find the culprit, maybe someone out there does.
Oh, another weird thing about Safari and Apple's own site:
People using Safari 4 see the double text-entry box at discussions.apple.com, those with Firefox don't. You'd think Apple would fix this by now.