Figure on 6 months before most of the benefit is realized, but you do not need to necessarily wait to plant either. Long as you are 5.5 and up, I'd lime it asap and plant it whenever you want to, unless you are doing something tricky like alfalfa. Some clover and beans will be fine to start.

Pelletized lime will work a little faster than ag lime due to the smaller particle size (several particles make one pellet).