Managed to set up the new firewall computer to work with the Kensington USB Webcam using the se401 kernel module. New comp had a different USB type than the previous Intel motherboard, so new kernel time! (didn't realize that until an hour into debugging why webcam no longer output pictures :-/
Ok, so the latest version of MythWeather in gentoo as of this date is still having issues because the data from the weather info provider changed in format. So, I decided to grab the latest from MythTV - apparently the mythweather-revamp work has replaced the broken older version of MythWeather.
So grab the latest plugin from mythtv.org's svn repository: (I put mine in the directory mythtrunk-2007-07-22)
# svn co http://svn.mythtv.org/svn/trunk/mythplugins/ mythtrunk-2007-07-22
[snip]
Checked out revision 14027.