Firefox Slowness with localhost on Vista (or XP with IPv6)

I recently encountered an issue with a web project running locally and VERY slowly loading pages (more specifically images) in Firefox. Thanks to this post by Dan Wahlin, I was able to resolve the problem.  Per his post:

It turns out that the slowness is caused by an IPv6 issue with DNS and can easily be resolved by turning IPv6 support off in Firefox while doing localhost testing.  To make the change, type about:config in the address bar, locate the network.dns.disableIPv6 setting and double-click on it to set it to true.  This does the trick for the Firefox localhost issue on Vista and everything is running fast again.