I just installed (and tweaked a bit) WordPress on a test site, to decide if I really want to use it or not (leaning towards using it now). Be forwarned, I suck at graphic design so I just downloaded and (slightly) modified an existing style.
Please visit http://test.downinit.com/ and try to break things. Feel free to reply to any page there (they're all test posts), or post back here any comments, criticisms, bugs, etc... Some stuff isn't done yet (forum and wiki integration for example), but most of the WP changes should be in working order.
I've only tested in Firefox 0.9, Galeon 1.2.5, Opera 7.11 and Konqueror 3.0.3, all in RedHat Linux 8. Both my windows machines are currently down for repair, so any testing with win browsers is appreciated.