[Linux Documentation Project http://tldp.org] — great site. Howtos, guides, excellent place for the newbie to start.
[usenet http://groups.google.com] — newsgroups searches via Google. If you've got a problem, chances are someone else had it before you, and posted a solution to it on usenet.
[O'Reilly http://www.oreillynet.com/] — Linux-friendly book publisher. They put quite a lot of documentation on the web for free.
[USALUG http://usalug.org] — Great support forums, open to all distros.
[OpenSuse.US http://opensuse.us] — Support forums dedicated to Open Suse.
[Experts Exchange http://www.experts-exchange.com/] — peer-to-peer knowledge base: query the volunteer experts on most technical subjects. Interesting… it looks/works like the old AskMe.com.
[linuxprinting.org http://www.linuxprinting.org] — The first stop for all your Linux printing needs. Everything from drivers to supplies. Of particular interest is the [database http://www.linuxprinting.org/database.html], where printers are rated from Works Perfectly to Paperweight. Save yourself time by heading here first.