Well, interesting question. Things are changing a bit, where more "brick and mortar" schools are offering online degrees. There is a such a huge market they are missing, they figured they better get in on the fun.
Here are some questions to ponder:
1. First and foremost, please don't let the availability of an online degree overshadow the need to have some strategy and planning. Make sure your employers will respect that online degree. As you indicated psychology, it should be one that is reputable to most doctoral programs, or you will find yourself retaking a lot of classes.
2. Find out if the degree is marked any differently than your traditional classroom degree.
3. Find out if the same instructors teach the classroom settings vs. the online program. For example, I took some Industrial Engineering classes that the class was videotaped. Same everything; I just did not sit in the classroom.
4. Be true to yourself. It takes an unusually high amount of self-discipline to complete those online programs, and it's easy to get behind. There is something about 'having' to go to the class and sitting through the material. Depending on the class and your learning style, the ability to interact, discuss, ask questions, etc. is vastly superior in the classroom than on-line.
5. Again, depending on #1, one of the values of going to school is in the networking program. You want to make contacts, not only professional ones, but academic ones for PhD/post doctoral activities.
Just do your homework

. Make sure the program is right for you, and will help you achieve your goal.