thanks for your question. Are you sure you will be using a 32-bit OS? I would definately recommend you consider 64-bit OS, as this is what the processor is typically running for XEON 5500.
Otherwise, here is a great resource for learning the basics of memory configuration for Xeon 5500: http://communities.intel.com/community/openportit/server/blog/2009/05/05/nehalem-memory-help-im-lost
Let us know if this answers your question.