Jimmy Nilsson has a very nice article over on FTPOnline titled "Simplify Your Efforts With DDD". Jimmy overviews many of the key concepts within DDD such as:
- Use repositories to "help factor our certain logic"
- Use Factories to create objects
- Use aggregates as "the processing unit"
It's a very nice 2 page writeup on the basics of DDD. After reading his review if you haven't already be sure to pick up Domain Driven Design to get all the gory details.