The following sites have indexes of software useful for the Webmaster, whether scripts or executables, all perform some useful function. Part of a webmasters role is to keep a handle on emerging software and tools, as theres always a need to improve performance or procedures...
TuCows - Webmaster Resources
Of the 30,000 or so newsgroups out in the wild, there are a few with a focus on Web servers, technologies and standards, and other topics of general Webmastery. All are indexed by the search engines that index newsgroups (Deja.Com, Altavista etc.)
Focuses primarily on the administration of the most popular unix web server 'Apache'. This is a busy newsgroup and has a failry high calibre of postee.
Is a little more specific, focusing more on the specific role of a webmaster, but like any newsgroup, get's it's fair share of Newbies and Spammers. There is an FAQ being written currently for this newsgroup.
Apache Performance Tuning
NT vs. Linux Server Benchmark Graphs
One of the most important responsibilities of a webmaster, is monitoring developments and new web related technologies so that your aware of them before your pointy haired boss sends you an email asking if you have a policy for implementing them yet.
A webmaster should be familiar with the following technologies, and The Worldwide Web Consortium (W3C) should be the first place you go for definitive answers about specifications surrounding these topics...
HTML (hypertext markup language)
CSS (Cascading Stylesheets)
Tim O'Reilly on Webmastery
Extropia's - what is a webmaster?
The nuts and bolts of the web
CIO Magazine - Job Descriptions
HeadHunter - Recruitment