GRE and online schools?

I'm thinking of going to Grad school. The thing is I don't have the time really to do it so online will have to work best. Through my researching schools to try and find the program I want, some schools say you don't have to take the GRE or any grad school admittance test. I thought you had to take it for any school. Has anyone gotten a degree from an online university? and if so did you have to take any test to get in? Thoughts on online colleges (they are becoming more popular for those of us who can't quit our jobs.)