Apart from using virtualization (i.e. running windows on your mac) there are
a few options I would like to recommend.
1. A superb free service called browsershots (http://www.browsershots.org)
where you can send in your url and choose from a list of browsers you would
like screenshots from. It's not fast (the machines doing the screenshots
donate their time on a voluntary basis) but it works pretty well and it's
2. There is a project called ies4osx which runs IE/Win 4-7 through Wine (a
sort of virtualization software to run single Windows programs on mac/linux
etc). It's pretty buggy, but works acceptable. There are supposedly licence
issues in doing this, but I'm no expert on those. The project can be found
at http://www.kronenberg.org/ies4osx/, there are instructions on that site
on how to install and configure Wine (and X11, which you need) on that site
Hope this helps!
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