The SUSE YaST package repositories are not properly listing their packages. The
package list for SUSE 10 OSS RC1 works fine, but the final release is not. If
you add this source to your YaST software sources list:

mirrors.kernel.org/opensuse/distribution/SL-10.0-OSS-RC1/inst-source

You will get the full array of packages in the /suse/i586 directory, including
Mozilla Thunderbird and Sunbird, and many others. If you use this source instead:

mirrors.kernel.org/opensuse/distribution/SL-10.0-OSS/inst-source

You will find that all of the same packages seem to be there in /suse/i586, but
they do not show up in YaST's software management screen when you try to add
them. I have tried to check some other mirrors, but they all seemed to have
problems connecting. I do not know if the problem affects all mirrors or not,
and unfortunately I just do not have the time to check them all. I suspect this
may be a simple problem in a configuration file on the servers somewhere, but
I'm not a SUSE expert.