I can't imagine doing web development without Firefox and Firebug. Unfortunately, debugging a VS2008 project with Firefox is much, much slower than debugging with IE or any other browser if you use the built-in webserver.

Luckily, a fix is available. All I needed to do was go to about:config in Firefox and set network.dns.disableIPv6 to true. A full load for a rather large and complex page went from 30 to 3 seconds!

from: http://weblogs.asp.net/dwahlin/archive/2007/06/17/fixing-firefox-slownes...