http://www.novell.com/coolsolutions/feature/11504.html A screenshot-filled YaST tutorial from Novell's Cool Solutions site.
http://www.suse.de/~sh/YaST2-Package-Manager Written to explain the big changes in YaST with v8.1, there's a lot of good information here on how YaST works.
http://portal.suse.com/sdb/en/2003/04/82_susewatcher.html Documentation for SUSEwatcher, including descriptions for the icons.
http://www.rpm.org Home for information on the Red Hat Package Management system. The site includes an online version of Ed Bailey's 2000 book, Maximum RPM.
http://linux01.gwdg.de/apt4rpm Everything you need to know to use apt for SUSE Linux.
http://www.nongnu.org/synaptic The Synaptic GUI for apt. Download the current source from here, if you can't wait for a new package via apt.
http://packman.links2linux.org Excellent repository for packages not yet included in the official distribution. Download directly or use APT.
http://speakeasy.rpmfind.net The U.S. mirror for the RPMFind search engine.
http://rpmseek.com Find more RPM packages here.
http://freshmeat.net A giant repository of Linux and other open source software, organized by date received. Thus, the "freshest meat" is at the top.