Why do you need to use Linux to test numerous web browsers?
I mean Firefox, Mozilla, Epiphany, K-Meleon and Netscape all use the Gecko rendering engine and should work the same on Unix, Linux and Windows. Internet Explorer uses the Trident engine and should work the same on WINE as on Windows.
Anyway, use VMware until MS adds decent support for Linux, BSD, OpenSolaris and other Unix/Unix-like distributions.
Regards,
Vincent