There are a number of threads on this subject - rather than repeat the information try doing a search.

One of the really big points to note about this method is that it causes the carbon and gunk to come off in 'chunks', therefore you want to take the engine completely apart to make sure that all of the 'chunks' are washed out of the nooks and crannies - they will plug up your fuel lines.

Also - I just picked up a great little crock pot from Walmart for about $10.00.
Bargains are all over the place!