The Harvard Anime Society (HAS) has 5 slots left to make a group rate and they will be paying through paypal (for the March 18th deadline). If you are going and are located in the cambridge/boston area and have not pre-registered HAS is offering to include you in their group pre-reg if you contact them by March 14th. see: www.hcs.harvard.edu/~anime
If you have issues with housing they will try and help you out with that (either by use of dorms or sharing a hotel room with their members).
Email them for more information and specifics at: firstname.lastname@example.org, email@example.com, or leave me a reply here.