Wonko-
Save your write up time for driving. Here's a link to one already done. The part #s may have changed since this was written, but the procedure is the same - EXCEPT you should not need to remove the drivers seat - just contort yourself like hell to get up in there. Good luck!
http://www.industryfigure.com/berkeley/Porsche/ignitionswitch.htm
BTW, with the really cold temps and a bad ignition switch, it's a good idea to throw your battery maintainer on the car until you fix the switch.
Here's a one page write up w/ out as much details, but again, good 'nuff (courtesy of Tool Pants on RennTech)