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.
The Xms and Xmx configure heap size. Heap memory is separate from PermGen space. Here is an in-depth article the subject. You can increase PermGen space with the -XX:MaxPermSize switch. 64Mb is the default.