You may choose to play Spider Climb as an instant; if you do, bury it at end of turn. Enchanted creature gets +0/+3 and can block creatures with flying.
I feel a little bad for anyone that traded any kind of cards for Web right before Visions came out. Web is a rare, Spider Climb is a common. Spider Climb is better than Web in every way--being able to play Spider Climb as an instant will enable you to kill many of your opponent's flying creatures with any old powerfull wall laying around. If you have Spider Climb on a creature that can block and kill an opponent's flyer, your opponent probably won't attack with the flyer and let you kill it. If you wait to play Spider Climb until your opponent's attack phase, you can then use Spider Climb to help kill the flyer by using it as an instant. Ask yourself --"will I be able to wait with this card to sucker my opponent into attacking?" If so, then ask yourself --"is paying one green mana worth killing this attacker?" The answer to the latter is most always yes. The sole ability to make any creature single-Bolt proof just can't be overlooked too. Here are a few great creautres to put Spider Climb on: