Below are the Boston Marathon qualifying times. There are only 25,000 entries allowed to run the race each year. The 2010 Boston Marathon is already closed because they have already reached this number of entries. (There are some spots left, but they are reserved for charities and other special guests) The point is, if you want to qualify for 2011, do it sooner rather than later.
I recommend using the 100 Day Marathon Plan if you are close to a qualifying time, and need to get just a little faster. This program is new to the market, so get an edge on your competition and qualify soon! Qualifying times achieved after September 26, 2009 are valid for the 2011 Boston Marathon. Below are current Boston Marathon Qualifying Times.
I was able to contact Jack Fleming of the Boston Athletic Association about the chance of qualifying times changing. I also asked if the rates would increase or more entries would be allowed. This is his response.
Given that 2009 closed at the end of January, and the 2010 event closed in November, we will have to be prepared for the race closing even earlier in preparation for 2011. For 2011, most options are under consideration, but the least likely at this point is a change in the qualifying times.
Not all marathons meet the requirements for Boston. If you want to run in Boston, make sure you are running on a certified Marathon course. There are three different websites that list qualifying marathons for Boston. U.S.A. Track and Field, and The Association of International Marathons.
If you are serious about qualifying for Boston, start training now. Registration for the 2010 Boston Marathon closed 157 days early. Follow the best training plan out there and qualify early, so you don't get left out in 2011. Good luck!