The Linux Plumbers Conference will be hosted at the Hyatt Regency Cambridge. It is highly recommended that you stay there, as there are no other hotels nearby.
There are plenty of restaurants and a Micro Center (a local computer retailer) 15-20 minutes by foot from the hotel. The closest restaurant is Stefani's Pizzaeria, which is a short 10 minute walk away. There are plenty of restaurants that will do take-out, and the hotel has a number of good restuarants for people who don't want to walk long distance for dinner. Fortunately, given the number of evening receptions and events planned by the conferences, there will only be a few nights when we will be required to find a place to dine.