I'm building back up to the half marathon distance after a number of factors took me off my game in the summer. The plan is to be capable of, and comfortable, running the full 13.1 miles by the end of 2010. After that ... well, we'll just see (wink).
This is my plan:
Running 4-5 times per week, with a gradual increase in weekly mileage and a recovery week every 4 weeks.