I do a five way rotation probably 3-4 times a year on the Zuke, and a 4 way every 3K on the work car. It does help. The tires last a bit longer over all, and it helps issolate any weird wear patterns and what causes them.
Front to back on directionals is the only way to do it unless your willing to break down the tires every time you rotate. For the Unidirectionals I do a combination of back to front, and side to side/ kitty corner things.
Just to let you know, with the work car I run through a set of tires about every 15K-20K with rotating, w/o about every 7 k.
I drive it a little rough.