Padmapper's a great utility for finding apartments. I used it before while looking for sublets in NYC. The site has a great UI and adds a ton of value - it's there just when you need it, it's like your Dropbox for apartment-hunting.

The founder behind it is a sharp guy too, here's a good interview with him - http://valleyloop.com/2010/10/11/qa-with-founder-of-padmappe...