Following on from Rene Schulte's directory of Windows Phone websites, and with his blessing, Ad Duplex have put together WindowsPhoneSites, which does exactly what you would expect a site with that URL to do.

Over to the site admin, Paulius Norkus, for the description:

This site was created as a filterable list of blogs, forums and other sites related to Windows Phone. We've tried to tag the sites appropriately so it's easy to filter out irrelevant sites and get a list of sites that match your needs. You can look for news sites in a specific language or country to tip them about a localized version of your app. You can find forums or blogs in your language. Or find and join a community site in your region.

If your favourite site is not listed, feel free to suggest them to the team!