I like Davis Square, but it's at least a 30 minute walk to school--maybe more. I'm thinking about moving out that way because I like the vibe. I live in Cambridge right now, almost in Somerville. Somerville is kind of the cheaper location to live in. You could live in Union Square or Inman and still be pretty close.
Last year we had to go with a an agent, because we weren't from the city. This year I hope to have better luck on my own.
Oh and if you get a place for Sept 1st, there's a decent chance you won't get it until the 1st and school starts before then.