Boston T & Shuttle Bus
Nearest T stop (subway, metro, ...) is Lechmere stop on the green line. There are shuttles from the airport to get to the T and essentially any other place in Boston.
From Kendall Square (a block away from the Stata Center), there is a "Wave" shuttle bus that will take you to and from the mall across the street from the hotel. Hours are 9-7 on Saturday and Monday and 12-7 on Sunday.
Parking for conference attendees at the hotel is available for the discounted price of $18/day (single entry). Parking is also available at the mall across the street for $3.99 for up to 10 hours.