I am not a real-estate broker, but I do have several properties that are in various phases of tenancy. I also travel frequently so see the update timestamp on this webpage for the last update time.
www.114charlesstreet.com (I live here currently, avail 7/24/09 when I leave for Europe)
www.6adamsshore.com (weekly rentals available, summer filling now)
www.224chestnutstreet.com (looking for full-time rental tenants as of 7/31/09)