Having worked full-time at a camp for almost five years (plus many summer in high school and college), I thought I'd share some brief thoughts on being successful at sending your child off to camp:
1. Raise them to be able to handle being away from you. Instill them will self-confidence, common-sense and a healthy fear of harmful things (our job as parents, after all, is to raise them to be able to live on their own as successful adults).
2. Don't tell them to call you if they get homesick. Write to them, but don't call them. And when you write, only talk about what they're doing at camp. Don't mention how much you miss them or what fun things they're missing out on at home. Just focus on the new friends and the fun they may be having at camp. Most homesickness is created by parents. Their counselors, while trained to deal with homesickness is good ways, have plenty to deal with as it is.
3. Talk up camp ahead of time--focus on all the fun things they'll get to do, new skills to learn, new friends to make, etc. Don't focus on your own fears or concerns.
4. Help your child prepare. Teach them to roll up their sleeping bag, turn on a shower and bathe themselves, how to spend their money wisely (budgeting over a few days), etc. And don't be upset if they come home without having rolled up their sleeping bag, not showered and used all their money on candy.
5. Have your child pack their own suitcase/bag as much as possible. They're the ones responsible for bringing everything home--they need to know what's in there. And if they pick out their outfits, they're more likely to wear them (I know plenty of kids who don't change their clothes during the week.
And this is a bit late at this point, but maybe keep this in mind for next year: try and attend camp together as a family before hand if you can--even if just a visit. Our Bible camp has several family camps. One is over Memorial Day weekend where you attend for a minimal fee in exchange for helping get the camp ready for summer.