TikiWiki Incorporates MapServer4
The latest release of TikiWiki has embedded support for MapServer 4 and could be useful for community mapping projects. I haven't looked too deeply at exactly what functionality is included but it will be interesting to see where they go with this.
I've been keeping my eye on Tiki for quite as while as they have been under going incredibly aggressive release cycles for over a year. It's impressive what they've done in such a short about of time. I've never dug in because initially I was put off by a CMS that kept it's documentation in PDF and the fact that it's ugly. It might be time to reinvestigate.
See also: WikiSoftware, GisResources