I usually use booking.com but like pintohoo points out, these are for shorter stays. I think airbnb is good for longer stays. Six weeks is really neither here nor there. ie too short for a rental and too long for a stopover. I think airbnb gives you an option for that in between length of stay for say six weeks where you can get a fully furnished place, utilities, internet, etc all included in the price with a significant discount for this length of time.
