Frameworks & Guides
SETT (Joy Zabala) This is a popular framework and eval tool; acronym stands for "Student, Environment, Task, Tool" -- understanding the first 3 will lead to the right tool.
Wisconsin Assistive Technology Initiative Assessment (PDF)
Council for Exceptional Children's Assistive Technology Consideration Wheel
Virginia Assistive Technology Resource Guide (PDF)
Apps
From the recent (10/2012) QIAT listserv thread on evaluation: ATEval2Go