I went back to school for a PhD at the age of 41. I was burned out on programming, I was lacking in theory, and I was ready to see the other side of the country for a few years. I'm now in my fifth year of that. It might take me another year for the PhD or it might not happen, but it has been a great adventure either way. It has opened up some other opportunities for me and helped me to recognize the areas of programming that I truly enjoy.
I sold a house when I moved and used that equity money to make the house payment at my new location while in school. If you don't have a lot of kids and/or your spouse brings in just a little money, you can make it okay on the graduate assistantship alone. My assistantships have been paying $2500/mo. The problem right now is that housing in the USA is very expensive almost everywhere, so you'll need a smart plan to deal with that.
