Midrange
Morrison House (Bed and Breakfast)
221 morrison avenue, phone: +1 617-627-9670, (http://www.morrisonhouseb...). 4 rooms, near public transportation.
Holiday Inn Boston Somerville
30 washington st., phone: +1 617-628-000, fax: +1 617-628 0143, (http://www.hi-boston-some...). just two miles from downtown boston and four miles from logan international airport. includes a photo gallery, rates, availability and on line reservations.
AmeriSuites
116 riverside ave, medford, ma, +1 781-395-0077, (http://www.amerisuites.com/). located off of i-93, near medford square. this hotel is 2.5 miles from davis square and 7 miles to the airport.
Somerville is, as mentioned elsewhere, a heavily residential area; hence, there are few hotels. There are some bed-and-breakfasts that are not well-publicized; if you are visiting someone who lives here, they may be able to help you find one. Otherwise, you may do better to stay in Cambridge or in one of the outlying suburbs along Route 93 or Route 95.