I am currently getting my Masters degree completely online through Florida State University. I love the program, but I do think it is more challenging and more work doing it online than if I were getting the same degree in person. The only reason I'm doing an online program is because my state does not have *any* graduate programs in what I was interested in, and I need to keep my current job in order to pay for school, so moving wasn't an option.
I would recommend, rather than strictly limiting to online schools, check out what your local schools have to offer for people working full time. Some online schools can be *VERY* expensive, especially if they are state schools that you would be considered out-of-state for. I will most likely have to take one required course through University of Phoenix Online because FSU doesn't offer it online, and that one course will cost me twice as much as I spend on an FSU course. Cost-wise, it can really make sense to look at local community colleges, at least for the first two years, and then transfer to a four year school to complete the degree. A lot of community colleges do offer at least some classes online and many offer classes in-person in the evenings.
I have found that you have to a) be super organized and good at budgeting your time and b) be extremely self-motivated in order to do well in an online program. In many cases, classes can be very much "self taught" - you do the readings and the assignments without much, if any, input from the professor - no lecture and not much interaction with the professor unless you email a question or post a question on a classroom discussion board. Just something to keep in mind when deciding whether an online program is right. This also depends on the school. The program I am doing at FSU is run almost like an in-person class - we "meet" in a virtual classroom once a week either from 6-8 or 8-10 pm depending on the class and the professor speaks into a microphone to lecture/answer questions and sometimes has a powerpoint presentation to share. Those with microphones on their computers can also ask questions with the mic, or type it into a chat box. Most programs I've seen are asynchronous/on your own time kind of things where you just need to log in and read/post to a discussion board or e-mail list a specified number of times each week.
This site has good information about accreditation.
