I currently only have macs for development. My site looks good in the Chrome, safari and firefox but not in IE 8. Normally I'd say too bad, use a proper browser, but that is probably not going to work with my user base. Are there ways to emulate IE 8 on the mac? BTW if somebody wants to have a look: here is the site.
In IE 8 only the 1 first column is displayed. In chrome or firefox I don't see any warnings, apart from some javascript warnings which I fixed locally (but not on world wide web yet).
There is CrossOver (proprietary 51$). It "allows many Windows-based applications to run on Mac OS X using a compatibility layer". It is based on Wine.
It works OK (JavaScript + Flash). They provide automatic installation for Internet Explorer 6 and 7. For Internet Explorer 8 one more step is required to get what they call a CrossTie.
You can also try WineBootler (free and based on Wine too) but it does not work very well (no JavaScript support).
Edit: I recommend to use a VM from Microsoft modern.IE website, this is what people do.
The only way I know to do this is to run Windows with a program like Parallels and use IE that way.
I would recommend running Windows 7 and IE 9. IE 9 is not only a competent web browser, it can render pages as IE 7 or IE 8 by using the included developer tools.