Lots of great advice here. However, this is not an easy process if you want your parts to look good. Buying the materials and chemicals to do this process is not cheap. Experience is required.
The company I deal with has been doing this for almost 20 years and supplies finished goods to many luxury car dealers in SoCal. I am not allowed to list the brands, but they are Japanese, American and German. This service can cost as much as $4000 through a dealership.
A number of forum members have taken advantage of this service. At 60 cents per sq inch, I believe this is the most reasonable price you will find anywhere. This price is low wholesale normally offered only to large volume clients.
If you want to see how this is all done, this is an excellent video showing all the steps and stages.
YouTube - Water Transfer Printing Process