I don't know if they offer a Masters Program but I've heard wonderful things about the courses at PBS Teacherline. They offer a lot more than just technology and at one time had classes with connections to the Natural History Museum that sounded like fun.
The New York Institute of Technology has a great program for teachers. Not all the classes are offered online, though. One can register for the first 30 credits through NYC's Teacher's Untion, UFT at substantially reduced cost, and the last two classes are full freight. I'll be graduating in May next year with an MS in Instruction Education. I believe that FDU - Farleigh Dicksenson University in NJ also offers this Masters Degree. NYIT has 2 tracks - corporate training and K-12 education.
Indiana University has an online Instructional Systems Technology (IST) masters. I've heard great things about it. I did the residential program and I do recommend that. Check it out at http://www.indiana.edu/~istde/
In the past, the program has been seen as very corporate (training) oriented, but these days I see it as a good balance between education and corporate sectors.