Hi Neil,
We also flew internal to Boston and needed to get from Airport to hotel. On advice of our friends (who had landed a couple of hours earlier) we took a taxi which cost around $20 (incl. tip) and only took 15 mins (to Langham Hotel). BOS is pretty central compared to airports in other cities.
Hope this helps
James
Cheers James - taxis for me are usally the easiest if the not the cheapest option, but I am sure I remember some of the more regular visitor's to Boston saying something about some kind of train thingy which sounded quite interesting and I just wondered how easy/cheap that was.
Neil:)