Depending on Engine, it is Not to Hard.If you are looking to Buy & INSTALL the Cruise Control:Purchase a Kit made by ROSTRA Precision Controls. They are the Oldest & Best ( in my opinion). I have Installed these Kits for 18 years & have less than 3% return. The Kit I recommend is a Fully Electronic Cruise & you can get it with the Universal Handle that Mounts on the Steering Column. Or the Wireless Steering Wheel Control (recommended) It is a little more expensive, but looks Great.The Actual wiring is a pretty simple 6 wire hook up. Other than Mounting & running the wires inside, it should take you apprx. 2 - 3 hours if you have some Mechanical experience. 40 minutes for me...Here is the Parts you will need if you go with the ROSTRA Cruise:http://www.rostra.com/ac-search_results.asp
Stay away from Cruise Controls that use Magnets or Vacuum.
If you need any other help Installing or wiring let me know.