This excerpt taken from the HPQ DEF 14A filed Jan 29, 2008.
From Points West via I-90:
Follow the Massachusetts Turnpike/Interstate 90 East to Exit 25South Boston. At the top of the ramp, bear left towards Seaport Boulevard. At the first set of lights, proceed straight onto East Service Road. At the next set of lights, take a right onto Seaport Boulevard. The Seaport Boulevard entrance to the Seaport Garage is located ahead on the right.