If you truly must have ActiveX then as far as I know you'll have to use Windows. You don't want Virtual PC - it doesn't work for Intel-based Macs. You can use something like Parallels, Fusion vmware, or Boot Camp itself to run Windows. The first two allow you to run Windows in a virtual machine environment - i.e., you can have Windows fully open and running while booted into Mac OS X. Boot Camp allows you to boot exclusively into Windows XP.