From Open Sourcery today:

My good friend Felix in Germany runs a great web site with a fantastic service for developers wanting to see their web sites on a Macintosh using either Safari, IE 5 or Mozilla (Mac Screenshot Service).

Fundisom.com includes: CSS Tricks (layout and hover techniques), PHP Scripts (a good selection of ready-made scripts), and a PHP mirror function that allows for server copying without an FTP connection.

This can be a life-saver if you need to check your page quickly and easily and just don't have the time to find/fire up a Mac (or don't have one, for that matter). There are other services of this type mentioned in the comments as well, including the well-developed site iCapture.

There used to be a tool that would allow you to do this with multiple popular browsers at the same time, but I'm not sure what ever became of it...