Vermeeren et al. survey the UX evaluation methods in use and find that the field needs low-cost methods for measuring UX in early stage designs:
Vermeeren, A. P., Law, E. L. C., Roto, V., Obrist, M., Hoonhout, J., & Väänänen-Vainio-Mattila, K. (2010, October). User experience evaluation methods: current state and development needs. In Proceedings of the 6th Nordic Conference on Human-Computer Interaction: Extending Boundaries (pp. 521-530). ACM.
Desiree Sy describes how AutoDesk/Alias integrates UX research and evaluation into their agile dev processes:
Sy, D. (2007). Adapting usability investigations for agile user-centered design. Journal of usability Studies, 2(3), 112-132.