Something near and dear to my heart (is that disturbing?):
Two great articles by Jeff Patton of AgileProductDesign.com offering 12 best practices for UX in an agile environment.
12 Best Practices for UX in an Agile Environment – Part 1
12 Best Practices for UX in an Agile Environment – Part 2
Jeff’s 12 best practices (sans explanation):
1) Drive: UX practitioners are part of the customer or product owner team
2) Research, model, and design up front – but only just enough
3) Chunk your design work
4) Use parallel track development to work ahead and follow behind
5) Buy design time with complex engineering stories
6) Cultivate a user validation group for use for continuous user validation
7) Schedule continuous user research in a separate track from development
Leverage user time for multiple activities
9) Use RITE to iterate UI before development
10) Prototype in low fidelity
11) Treat prototype as specification
12) Become a design facilitator