(As per Catman's request):
The Massachusetts Bay Transportation Authority website can be found at http://www.mbta.com and subway maps can be found at http://www.mbta.com/schedules/maps/spider/

Taking the bus costs 60c, the T (subway) costs 85c.

Using mapquest, you can see where Harvest is in relation to Boston/Cambridge:
http://www.mapquest.com/cgi-bin/ia_find?screen=ia-map-result&link=ia-map-result&uid=u6t20dnebccosayv
takes you to a map of the two cities, and Harvest is marked by the red star in the upper left hand corner of the map. Highway 2A is Massachusetts Avenue, along which the No. 1 bus runs.
The airport is off the screen to the right - highway 1 passes it.

Boston is a relatively compact city - you should have no trouble getting from A to B in minimal time.