Fitness: Anyone who can fit in a harness can top-rope. Being in great shape may help you learn faster, but climbing is primarily a sport of balance and coordination, and doing a little rock climbing can be a great way to motivate yourself to stick with an aerobic fitness or weightlifting program.
Instruction: Personal instruction is required for rock climbing. Although formal certifications are not given, the equipment and environment for rock climbing pose risks, and it's important to have a knowledgeable person show you the equipment and teach you to use it properly. The good news is that basic safety rules can learned very rapidly, and are taught for free at most climbing gyms.
Equipment: If you just want to climb at the local gym every once in awhile, you don't have to buy anything. Gyms rent shoes and harnesses, and often provide belay devices and locking carabiners for free. If you wish to climb in the gym regularly, you'll probably want to buy a pair of shoes, a harness, and a belay device with locking carabiner, which will run a total of about $150 to $300, depending on the quality and style of equipment you choose.
What is the equipment?
Climbing shoes: These come in many styles, from "board-lasted" beginner-oriented shoes (with a stiffer sole), to flexible all-style shoes, to shoes with ankle protection for outdoor or crack climbing, to intensely shaped shoes (think ballet toe shoes!) for very aggressive "sport climbers" -- those gravity-defying climbers on the hardest routes. They all have a sole and wrap of smooth sticky rubber, which makes it easy to "stick" to the rock. You want a pair of shoes that you can lace tightly enough that your foot doesn't move inside the shoe but that don't hurt you or cut off your circulation. There'll be plenty of time to experiment with pain if you decide you want to win the X Games.
