Can anybody recommend a good tool for emulating IE6? Rather not have to go and install an old copy of XP somewhere.
People generally use VMWare, or another virtualisation tool, to do this. At least where I work :)
IETester allows you to install IE versions 5.5 -> 8 on a single machine.
If you are running a Windows OS, you can install MultipleIE. It will allow you to run IE6 as a standalone.
http://tredosoft.com/Multiple_IE
Not sure what your OS is though.
Microsoft Expression Web Super Preview (which is now part of Microsoft Expression Web 3) has the capability to show you how a page would render in IE6, also has some nice features to overlay an IE7 render or an image so you can see where those 1 pixel discrepancies are occuring
https://browserlab.adobe.com/ gives you an image of your site in various browsers. Not a real world experience but handy nonetheless.
http://spoon.net/browsers/ Spoon lets you create web-hosted versions of your existing Windows apps that run instantly from your web site, with no install. Spoon has a gallery of browsers that you may launch including:
Microsoft Internet Explorer 8, Internet Explorer 7, and Internet Explorer 6 Mozilla Firefox 3.5, Firefox 3 and Firefox 2 Apple Safari 4 and Safari 3 Google Chrome, Opera 10, Opera 9
Litmus lets you test your site in dozens of different browsers.
I found recently that you can do this quite nicely in windows 7, using XP Mode. You need two virtual hard drives set up, but you can then create shortcuts on your win 7 desktop to 'open' IE6. There's a good walkthrough of how to do this here:
http://articles.sitepoint.com/article/ie6-ie7-ie8-win7-xp-mode/1
On Windows 7 you can download XP Mode, which gets you a fully-licensed version of XP. It integrates nicely with windows 7, and it never expires like the free VPC images.