The rotation scheme I use is:
Spare to Right Rear
Right Rear to Right Front
Right Front to Left Rear
Left Rear to Left Front
Left Front to Spare.
It sounds a bit confusing but it's really sort of a counter-clockwise rotation.
Believe it or not, I was bored enough at work one day to draw it out on a spreadsheet.
Take a look at http://groups.yahoo.com/group/midatlanticjeepers/files/
and click on the rotation.xls spreadsheet to download it. I laminated a copy of it and stuck it to the inside of my tailgate.