BrowserCam is a very cool service that allows you to obtain screenshots of web sites in a number of different browsers, so you can see what your site looks like to people using IE, Safari, Firefox, or Opera on different platforms. It is, however, on the spendy side - one day's access is $19.95. But, a year's access for a group of 10 people is $399.95 - this is originally intended for a company, but if you get 10 people together you can get a year's access for the price of one day.
People have been using Fundable.org to co-ordinate such group purchases. Here's one that I've joined.