On my Linux laptop, I use VirtualBox with Win7 as a guest operating
system. Works very nicely, actually, and it's always with me if I need
to do some testing.
Mike - the problem with browserstack is that it doesn't help you debug
javascript. Sometimes, the only way to find out why an app works
everywhere else but fails on IE8 is to run it in the debugger on a
real live running IE. And actually, the IE10-pretending-to-be-IE8
debug environment is actually quite tolerable, although Chrome's
debugger and Firebug are much better.
Ian