While registration information is up in the air for the 2014 Boston Marathon, a few things are very certain. First, the 118th Boston marathon will be held on April 21, 2014. And second, after the tragic events of this past year, gaining entrance will be exceptionally hard for the event.
The Boston Marathon already has very stiff qualification criteria in place to ensure that the field is top-notch (view the criteria here). Due to registration limits that had left some qualified athletes unable to register, in 2012 the BAA initiated a pre-registration process that favored the fastest times within each division.
If the qualifying time for your division is 3:10, for example, but you ran a 2:53, you received a priority registration opportunity. In other words, you could register before someone who ran a 2:59; they in turn could register before someone who ran a 3:09. There were specific "windows" for these pre-registration waves, but overall the process went smoothly.
However, people who had qualified for Boston were still locked out as the amount of delegated spaces for the race had filled within a few hours of open registration—by open I am referring to athletes who were within the last five-minute window of their qualifying time.
In other words, achieving the current standard of 3:10 for your age group doesn't automatically gain you entry. At the present time you (1) need to have your qualification solidified by September 1 and (2) need to run at least five minutes faster than your current standard, ideally 10 minutes faster if possible.*
*Note: This is based off of the 2013 registration process and could change in advance of 2014 registration. While you absolutely want to have a qualifying time by September, you might not need to be as fast as I am proposing here (but it can't hurt!).