The first thing you want to do is check for accreditation. Online universities are fairly new and because of this many employers may not trust their curriculum, this is particularly true in the education field. The accreditation process establishes certain educational standards in the curriculum and makes it more trustworthy to potential employers.
The next thing to check for is their education bachelor degree program. It's important to make sure that they have the right bachelor degree program that you're looking for. You may want to compare bachelor degree programs across different online universities. Sometimes an online university will tailor the bachelor degree program to a special area of interest that may or may not suit your needs.
After you've gathered a couple of online education bachelor degree programs that look good, perform a few google searches on the online universities. Look for other online education student's reviews of the same or similar programs. It can be helpful to find online education forums that discuss online universities, classes, etc. In the reviews look for things like customer service, application assistance, financial aid assistance, etc
The last thing to do is to apply for more information from each of the online universities about their bachelor degree programs. Compare all of the above factors and factor in other things like tuition, flexibility of schedule, and options for extending the program (in case you have to take time off).