What is the best way to structure the tempdb database?

The recommended configuration is to create a temdb Data file (not Log file) for each processor core on the server. This recommendation assumes that the storage you place the data files on can provide sufficient throughput for concurrent access to the data files. This is typically acheived via the use of a storeage area network (SAN) or multiple seperate physical disks.

What is the tempdb database and what does it do?

http://www.microsoft.com/technet/prodtechnol/sql/2005/workingwithtempdb.mspx

Should I create multiple tempdb database files?

http://sqlskills.com/BLOGS/PAUL/post/Search-Engine-QA-12-Should-you-create-multiple-files-for-a-user-DB-on-a-multi-core-box.aspx

How can I capacity plan for the tempdb database?

http://msdn.microsoft.com/en-us/library/ms345368.aspx