The Red Sox put tickets on sale on December 12th during their annual Christmas at Fenway event. As usual, select games for April, May, and (beginning on Sunday morning) September were offered for sale. While almost all the good seats together were sold in the first day, as of December 20th there are still plenty of standing room and obstructed view seats available. This is a bit unusual, as even getting 8 standing room tickets for a game in a single order was difficult in years past a week after tickets went on sale. This may signal a slightly smaller demand for tickets this year, which would not be surprising, given the team's finish to the season last year and the sagging economy.
The next chance Sox fans have to buy good tickets to games is likely to be January 30th, when the team is expected to offer tickets for the really "good" games this year -- June, July, August, and some weekends in April, May, and September that aren't available yet.