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.
InitialContexts are usually provided by containers that your code is executing within. To connect to JNDI directories that are located elsewhere, you usually need to do so in a vendor-specific way. You'll have to consult some extra documentation to figure out what else is needed. The JNDI tutorial will probably help you sift out most of these issues.