Physical Demands of USMC Bootcamp FAQ's

What are some good exercises to prepare for boot camp?

Start running every day. In boot camp you'll have to run on the streets, so best to stick with that. Do "pyramid pushups" or just "do pushups until you can't feel your arms, then do it again, and again" (same with pull ups).
The biggest thing is to run, run, and run some more!
Need a pull-up bar? Get a 3" pole from Home Depot, find some close tree branches, or go to a high school with them.
Check out the following web sites for workout ideas:
http://www.angelfire.com/ny5/shenandoah/Grunt/Bodyweight.html
www.navyseal.s5.com
www.teenbodybuilding.com/brent2.htm

The overwhelming response from Marines is to drink plenty of water and get the muscles working again with a light workout the following day. Eating protein, going swimming, and hanging out in the sauna also help.

Basically it's not unhealthy to run every day as long as you're in shape and have adjusted your body to the daily stress.
Start out on soft surfaces for 4 months, increasing your mileage not more than 10% per week. This will help you to avoid shin splints and other injuries. Also be sure to stretch every day. Shin splints and stress fractures account for 70% of injuries in boot camp (though half of that is probably guys trying to get out of training)
Once you've been running every day switch off between soft surfaces and concrete since you'll be running on concrete in boot camp.
Take it easy at first, stretch always, and quit smoking.

Don't go on a protein shake diet - Eat real food or your metabolism will get screwed up. Just eat a balanced diet (that includes a lot of protein) and work out.
Eating 6 small meals a day is a good plan.
Keep away from butter, pop, white bread, candy, junk food, sports drinks.
Exercise.