At the moment, I am running the Debian current stable version of Iceweasel (3..0.6).
Sometimes, you can experience some delay in displaying web pages because DNS lookups take too long. There are several solutions to this problem.
With my current version of Iceweasel, I advise you to install the following addon : DNS Prefetch.
To install it, just follow this link : DNS Prefetch
Once installed, restart your browser and pay attention to the speed of webpages loading.
Further informations :