Standalone IE (I use multiple_IE, not just IE6, due to the need for some clients to have their sites operable in IE5/5.5 - ) has a few other problems with javascript/cookies etc but its great for just checking your stylesheets.
Nope, I just tried there for the first time and it had a bit of a fit Not good if you do a lot of work with print stylesheets, but better than nothing. I have found IE7 to have a few interesting issues and shares some of the same problems with IE6, whilst fixing lots of others. I basically couldnt do my job properly without the multiple IE installer. If print stylesheet testing is important to you, you should try running virtual machines with different IEs installed in each. Its more hassle but the only workaround I know of apart from dual-boot, which is a pain. Good luck!