We released the Windows 7 application compatibility list a while ago, and have been updating it periodically to add new features. We’ve finally done the same for Internet Explorer 8: http://www.microsoft.com/downloads/details.aspx?displaylang=en&FamilyID=2ef7968e-a342-416f-ba78-594e7f075e83
Now, we can’t actually speak to whether something works or not, so for lists like this, we instead list whether the application is supported or not. (There are plenty of applications that work but are not supported, as well as plenty of applications which are supported but don’t work because they have a bug in them.) It’s up to you to determine if an application works for the business scenarios you use it for. But for most of the software in this list, support is often non-negotiable (things like Cognos, Dynamics, Siebel, or SAP). At 163 of the most critical web-based applications, this is a start which hopefully saves you a bit of time.