My daughter has been going to sleepaway camp since she was six years old. She sometimes gets homesick if she is kept up too late at night, but is always fine again in the morning. We don't allow her to take a phone or texting device, on the theory that it's best if she concentrates on having fun instead of being reminded of home. She usually does such a good job of concentrating on having fun that we don't get any letters from camp.
I did have some initial concerns about sending her to college gym camp, so before sending her I spoke with the camp director to find out how the kids were supervised. We ended up sending her last summer at age 8 and she did survive the week without getting lost on campus, although she definitely got away with plenty of stuff that wouldn't fly at Girl Scout camp.
I firmly believe that sleepaway camp is an important growth experience for kids. I wouldn't force a kid under age 10 or so to go if she didn't want to, but if your daughter is interested in camp and you present it as a positive opportunity (don't tell her how much you'll miss her!), she will most likely have a great time and become more independent and self-sufficient.