the following diagrams are taken from an excellent document from the Journal of usability studies called “Adapting Usability Investigations for
Agile User-centered Design” by Desirée Sy from Autodesk.
The first diagram simply captures a method for running parallel tracks of design and dev on an agile project. A great one for explaining how design and iterative development can work together… and more considered than the “ill just stay ahead of you guys” method
The second diagram structures a User Experience Card wall that helps keep design elements and where in the prototype / testing / ready cycle they are. Great !
Its really worth having a look a the entire document at http://www.upassoc.org/upa_publications/jus/2007may/agile-ucd.html