Hi Fluffy,
I did a search on,"How do I donate my body to science?", and pulled up some interesting info.
From the info I have found, you can't be an organ donor and then donate your body to science. You kind of have to choose between the two, and of course you can't donate your body if they have to do a post mortem, or if you have a communicable disease or if you are severly obese.
It seems as if the University of Sydney has a program where you can donate your body to them if you are within a certain geographical area (you have to contact them and they let you know) anyway, here is the link: http://www.anatomy.usyd.edu.au/donors/index.html#6
Other than that, it seems as if there are several programs here in the states that are like banks that you donate to and then they send out the "parts" as they are needed. You can fill out the papers online and they send you a donor card, and they handle all the expenses. Here are the links: http://biogift.org/index.html
http://www.lifelegacy.org/
http://www.medcure.org/questions.html
Hope this helps and good luck!