Excellent Partitioning Article
I've done some work with table partitioning using the "sliding window" scenario using KImberley's article as a reference point. I was reading through my Technet Magazine and found this excellent article on partitioning by Noah Gomez http://download.microsoft.com/documents/uk/technet/downloads/technetmagazine/40_47_simplifydb_desfin.pdf
I actually found there were a number of aspects of partitioning that didn't sit very well with what I was doing, try altering the partition function and/or partitions when your database is in use, some slight issues if your database is 24 x 7, however that's another story.
If you don't subscribe to Technet Magazine it might be worth a look, there are sometimes some real gems, there was a fantastic article last year on how to create load balanced sql 2005 servers behind your web site/farm.