Gary Halbert has a ton of great information on his site concerning newspaper advertising. There are samples there and information involving split runs; when to advertise; what section to advertise in; how to get people to respond; etc...

Marketing legend Melvin Powers also has a great book on classified advertising that you can find on Amazon for less than $10.

The same classified principles that work in newspapers work on Craigslist...

Aloha,

Jason Cain