If you are using windows and code for ie/firefox/opera... etc etc you might want to check out what your site looks like on a mac...

http://www.danvine.com/icapture/
http://browsershots.org/
http://fundisom.com/g5/

I'll add:

http://www.snugtech.com/safaritest/

Thanks guys, that was pretty useful. Since I don't know anyone with a Mac I am always curious.

It's the one envoroment I can't test on at the moment so it's great to at least be able to see an image of what the site is looking like. Hopefully one of these days I'll be able to afford to add a Mac to my collection of computers.

You can't forget BrowserCam.com. Free trial that lasts 24 hours, and gives you the whole variety: Windows, Mac, Linux, Fedora... the whole works. Screen resolutions ahoy, Flash/non-Flash... the list never ends.

Cool, I like it better. I think I need to get a Mac. Mandy

A cheaper alternative is to buy a copy of http://www.ehomeupgrade.com/entry/753/cherryos_mac_os

CherryOS, emulator for XP that can run Mac os X

However you still have to get a copy of osX. Not the best solution, but definitley cheaper than buying a macintosh outright.