This week's book giveaway is in the OO, Patterns, UML and Refactoring forum. We're giving away four copies of Refactoring for Software Design Smells: Managing Technical Debt and have Girish Suryanarayana, Ganesh Samarthyam & Tushar Sharma on-line! See this thread for details.
Aha, so you're not looking for an online version control system.
You can just download Subversion and set up your own server with it. If you're using Eclipse, then you can install the Subclipse plug-in so that you can check in and out from inside the IDE. NetBeans already has built-in Subversion support as far as I know (you don't need any special plug-in).