We have tested and confirmed that WBI works with the following browsers:
Internet Explorer 6
Internet Explorer 7 - get it at http://www.microsoft.com/windows/ie/downloads/default.mspx
FireFox 2 - get it at Firefox - Protect your life online with privacy-first products — Mozilla
Opera 9 - get it at Download the Opera Browser for Computer, Phone, Tablet | Opera
Google Chrome - get it at Google Chrome - Download the Fast, Secure Browser from Google (released September 4th 2008)
Any of the other browsers are a good choice and each has different characteristics that make them worth trying out if you use WBI heavily.