First, you will have to get XNA and Visual Studio 2008. If you are a student, head off to DreamSpark to get the student’s editions. After the installation, here are some good sites to get started on the basic:
- XNAResources for a tile engine tutorial
- Blue Rose Games for sprites and 3d tutorials
- XNA Development: Game Development for the Masses is a great place to start with 2D programming
- For everything else, there’s Ziggyware
Of course, the Creator Club for XNA has some samples and tutorials worth looking through too.