The SQL Server Metadata-Driven ETL Studio (MDDE) was an internal MSIT project first shown at the MS BI Conference last year. The initial release is now up on Codeplex. There isn't much information up about it yet, but I'm told that docs and examples should be appearing soon.
Essentially what MDDE gives you is a way to create SSIS package templates, which can be easily updated when your metadata changes. I'm currently playing around the code, and will hopefully have a walk-through up in the next little while.