I never had any symptoms. One morning I was feeling great and driving to work. Suddenly I started feeling like I was having a heart attack. I couldn't breathe and the pain in my chest was unbearable. I pulled over to the first business that looked open and went in and asked them to call an ambulance for me.
After lots of tests in the emergency room, it turned out I had gallstones and was scheduled to have my gallbladder removed the next day.
It was one of the worst pains I've ever endured in my life.
WebMD has an excellent and comprehensive set of articles on gallstones ranging from cause and symptoms to prevention, home treatment and a guide to help you know when to call a doctor.
WebMD's article on gallstones and the gallbladder
As for not being able to eat fatty food, the gallbladder stores bile needed to help digest fatty food. Without the gallbladder, the bile flows directly from the liver to the small intestine.
It isn't that you can't eat fatty foods, it is more that when you do, the fatty food flows right out of you almost faster then you can run to the bathroom. It also depends on the type of fat. If I eat a greasy fastfood hamburger, I have to find a bathroom almost immediately after. Yet I can eat cheese or icecream with not as severe of a problem. If I eat lean hamburger meat, the problem isn't as severe.
What changed the most drastically for me after the gallbladder removal was my ability to eat and digest grapes. Grapes are rather painful for me to eat now, whereas before I loved them. The problem is more worse with red grapes then green, but both I don't eat very often. Interestingly, raisins are fine. No problems.