I generally use Browser Shots to test browser compatibility but sometimes IE6 needs more views than they want to give me within what I consider to be a reasonable time span. Recently I found IE Net Renderer that lets me see it in realtime more or less without daily limits.

<rant>Take that IE6 and all the crazy people who still use it. I understand that technically some said users have no choice, but honestly—can we move forward in time to, say, 2009? Oh wait, that is now. While you’re at it, please get an answering machine.</rant>