I think Tom makes it sound a bit easier than it is.
See the link in my sig for info on my project.
I did the wiring myself, which makes it a lot more difficult than buying a harness that is ready to go.
Based on the questions you ask, I would suggest to do a bit more research before you start buying parts.
See the following links for more info:
http://autos.groups.yahoo.com/group/...nagon/messages
http://frost.bbboy.net/vwengineconversions
http://shoptalkforums.com/viewforum....3bc85c9391126f
When buying the motor, make sure to get as many parts as possible. Get the whole wiring harness and ECU (unless you want to go with an aftermarket engine management system).
It all depends on how capable you are and how much money you have to spend. The general rule of thumb is to make a budget, and then double it.
Rob.