engine clean-up

An added tip, and this may sound funny. I personally use Fantastic, but after you hose it off, use a leaf blower to dry everything. It prevents you from getting water marks all over the place and having to rub them out. Take your time and it will dry everything out very nicely!
 
note that typical degreasers work best on thin, light oily depsoits. If you have abunch of thick baked on grease, good luck getting it off with anything. That being said, simple green is my cleaner of choice, it works well and is not so strong that its overly corrosive. Some other products will stain paint and damage polished aluminum, castrol super clean in particular will damage most finishes.