Parking it's a great alternative for lazy people: you don't have to create content, design a site or pay hosting bills. Really cool.
Now, to make money with DP, you have to focus on 3 types of domains:
1) Type-In Domains with Traffic. Example: ringtones.com
2) Typo Domains with Traffic. Example: ringtong.com
3) Expired Domains with Traffic.
Good Luck,
Domain Parking
Learn the Basics, and the Secrets.