The knowledge bases listed below (in alphabetical order) are great resources for finding additional information on problems and solutions. Please feel free to add more as you use them.
Links:
[1] http://support.apple.com/kb/index?page=search&locale=en_US&q=
[2] http://kb.calyxsupport.com/kb/
[3] http://kb.endian.com/
[4] http://www.eventid.net/search.asp
[5] http://support.lexmark.com/perl/support/support.cgi?ccs=::0:0:0:0
[6] http://technet.microsoft.com/en-us/default.aspx
[7] http://kb.mozillazine.org/Knowledge_Base
[8] http://www.pciknowledgebase.com/
[9] http://kbase.redhat.com/faq/
[10] http://seagate.custkb.com/seagate/crm/selfservice/news.jsp?NewLang=en