Wondering when the best time is to plant and how long it will be until time to harvest?

This link tells you, by region, when the best weeks are to plant certain vegetables, and also has a chart telling how long they take to harvest:

http://www.clemson.edu/extension/hgic/plants/pdf/hgic1256.pdf

For example, in central S.C., soy beans should be planted between May 10-July 1, and will be ready to harvest in about 60-70 days.