Ok here's my technique which has been specifically developed for getting out of a suit as quickly as possible in the cold wet car parks of the UK's west coast.
Fold the top half of the boot down over your ankle. Put your index and middle fingers down the back, one either side of the achilles tendon. Prise the boot so that the heel is freed. If your boots are tight like mine, then they will still be stuck on tight!!, wiggle your toes to get a bit of breathing room at the end. Put your other heel on the toe of your boot and stand your weight on it, you can now pull your foot free.
THE TOP HALF:
If it's really cold, put your hands in your boots to warm the fingers up a bit!! Now, the next bit has to happen quickly. Unzip the suit and pull it over your shoulders, quickly pull it down the arms - doesn't matter if they go inside out, it's all about speed. As soon as your hands are out, get your rash vest off and put on your nice warm hoody!!
THE BOTTOM HALF:
This is where the technique splits in two. If you are not going to wear the suit again and will get the chance to rinse it out before your next session, try this; Literally peel the suit down your body like a banana skin so that it is inside out. Get it down to your knees as quickly as you can, then stand on it with one foot, pulling your other leg up, move the securing foot up and pull again. Repeat until your leg's out or nearly out - then use the same 'two finger technique' as the boots to get your feet out.
If however you need to wear the suit again then you should do the above on either some grass, or if you get desperate your board bag!! I haven't found an effective way of getting a suit off and keeping it completely clean.
Using this technique I can get my suit off and be dressed inside of 4 minutes, which is pretty quick!!
Rip Curl make some cool wetsuit bags. They are big circles of waterproof material which you stand on to take your suit off, then you step off and pull a drawstring which folds the 'bag' up around your suit and away you go!!
Hope this helps