The stickies on this site are a really great place to start off! Quail are tons of fun.
I used to sell craptons of eggs at the Farmer's Market until the food inspectors stuck their nose in and made it virtually impossible. They are notorious for just wanting to ban people from doing things, not at all interested in helping people do things right instead. Just be very cognicent of your local and state laws about food, and whoever buys from you - have them sign a waiver saying they understand that you are a hobby farm and not a commercial producer and they will not hold you responsible for any alleged illness that arises from the consumption of your eggs. Most restaurants are bound by law to purchase their ingredients from an inspected, licenced source. Some of them chose not to, but that's their choice, and if they were ever sued over an illness this is where the problems would start. You don't want any of that BS trickling over to you.
Yes I have kept my quail in cages in the same vicinity as my chickens but about 30 or 40 feet away from the chicken yard. If possible I always tend the quail first and then go to the chickens as there seems to be less health risk to the chickens from the quail as there is from the chickens to the quail.