It's like what Paradox explained. In addition to that, the Reserves let's you work part-time and is counted as 4 full workdays for only working a Saturday and Sunday that is scheduled for each month (Drills, UTA which is called Unit Training Assembly). The Reserves is that you are working for the nation, to protect and serve. You can be called at anytime to deal with any situations across the country (ex. Hurricane Katrina, the Presidential inauguration). You have also two weeks you have to commit to which is called Annual Training (14 days) per year. You do not have to take them all in a straight row, not with my unit I didn't have to. Your annual training could be in another city, state or even country to perform your training. The unit that you have joined might not exactly even be close by or sometimes not even in your state that you live in. In my unit I have several people that live far away and they choose to drive and fly (at their own expense to come to drills each month). You might be able to get a reimbursement but it depends on your unit. The only thing your unit will pay for if you live far away is a hotel for you. If there are none available on base, then you will be put off base.
As for being deployed, everyone has to be on a deployable status, not exactly that you'll be deployed. I've known a person that's been in the Reserves for quite awhile and is coming up on retirement but has not been deployed yet, only been to several trainings. I don't know how that person got away with that though. But you can also volunteer to be deployed if that is what you wish, you'll just have to work that out with your unit.
Make sure you talk and ask all the questions that you need to with the recruiter before you make your decision in joining. And if there is anything that the recruiter tells you that you'll get, like a bonus for example, make sure it's in writing and keep all records of your paperwork/documentation because you never know if something comes up or backfires.
Work on the ASVAB, and hopefully you don't have any health problems or anything else that will keep you from getting in. I personally had used in inhaler just for my coughing but never had asthma, so I was fine. I also only made a 45 for my entire score and got a medical position. But the higher the score, the more jobs you can choose from. The medical examination was done at MEPS (Military Entrance Processing System) where the recruiter will send you. You'll be spending the whole day there but the recruiter normally puts you up in a hotel if you live far away, because you'll have to get up early in the morning.
The military is great for benefits, you will have college money from the G.I. Bill which you can use right away. The tuition assistance is offered also. You will only have medical benefits while you're on duty, not when you're off. But your unit can offer you a discount on benefits for you that you shouldn't pass up if you don't have any at all. For dental, it's just a check up, other than that, they should offer a discount on that, too. But you'll have to get a civilian dentist otherwise.
Good luck when you go to basic training at Lackland AFB, San Antonio, Texas. Your recruiter should show you a video of how it's going to be like. You will be joined with the active duty and air national guard and you will all be treated the same. It is 8 1/2 weeks, when I went it was 6 1/2 weeks, that was back in June 2007. Your 1st week you will be called the baby flight, you'll still be in your civilian clothes but you'll receive your uniforms quickly along with your blues uniform. Do not expect to sleep, eat and just do everything that the MTI (Military Training Instructor) tells you, it makes it a lot easier on you. Take the yelling and the punishment when it's your fault or not. Do not stay at basic training longer than you have to, believe me, you're life will be more of a living hell. You'll be in the best shape of your life if you're not already. I'm gonna warn you about the snake pit in the chow hall, you cannot pass that. Meaning there will be a table of MTI's sitting there staring at you waiting for you to look scared, fall, just anything that makes you look like a target.
The great thing about being in the Air Force is that, it's the Air Force. The training that I went to last summer that was close by, it was only a few of us and the rest was the Army National Guard, they were not aloud to leave the base or drive their cars there. We were, we pretty much have it made.
They did away with PT during drill weekend because it took much time out of one day. Oh, by the way, in basic training, it is called the PRT (physical readiness training), after that it's just PT. And they did move the PT test up to every 6 months, that's because what I heard was that many people in the Air Force are overweight and the 2 extra weeks on top of the basic training is for more physical/active warrior training (i guess be more like