Scenario-Based Planning (or, How to Avoid Making Peanut Butter)
In my new role, I'm learning loads about the way the product teams plan, design and build products at Microsoft.
For the Data Programmability team (which now also includes the XML Team) our products and technologies have two 'ship vehicles', SQL Server and Visual Studio. (Update: Tommy rightly prods me and reminds me that the team also has deliverables to Windows, WinFS and in case of the XML team also ship bits with Office).
Of course, key to the success of future releases of your products is make sure you are investing in the right features (as well as fixing bugs). John Montgomery provides a high-level description of the planning process for 'Orcas' (next version of Visual Studio).