Extended Stay is a good recommendation.
Two other suggestions:
1) Hotwire.com While I haven't used it in other cities, I've noticed that in St. Louis, Hotwire seems to have hotels offering rates that are approximately 1/2 of their standard published rate. The only catch: hotwire will quote you the room rate and the general area of town that it's in - as well as the number of stars that the hotel is rated - but you don't know the hotel name until after you pay for your room on-line. As a comparison: I stayed in a Hampton Inn (very nice, free sausage/egg breakfast, etc.) and it was rated a mere 2 1/2 stars. Likewise, a reservation at a 3 star hotel turned out to be a very nice Doubletree hotel. So, don't automatically assume that a 2 1/2 or 3 star hotel is a dump. Also, if it says that the room has a kitchenette, odds are that it's an extended stay (or similar competitor).
2) If you're going to be there for a month, I'd call around at all of the 'decent' chains (Holiday Inn, Hampton Inn, etc.) and ask for a quote for a month or two. If you're going to commit for that long, lots of hotels will offer to give you a great rate, even though you might assume that they're 'high' to begin with. Of course, if you have no qualms with a Motel 6 or a Super 8, they'd offer you a discounted rate for a month or two long rental as well.
However, I don't know if you need a place with a kitchenette or not...if you were going to eat out anyway, it's not a big deal...but an extended stay-type place where you can cook your own food would save about $10-$15/day for not having to eat out all the time, although a free hot breakfast every day would help pay for part of that.
--Peter