Apple has updated iAd Producer (http://developer.apple.com/iad/iadproducer/) — its tool for developers and designers who want to “design and assemble high-impact, interactive content for iAd” — to version 2.1. The upgrade adds support for the Retina display on the new iPad, Twitter integration, and the ability to include WebGL content.

iAd Producer automatically manages the HTML5, CSS3 and JavaScript behind your iAd. For advanced developers, iAd Producer offers sophisticated JavaScript editing and debugging, along with a powerful extension mechanism that enables them to create and re-use their own page templates and components

iAd Producer is available for download on Appleā€™s developer web site. It requires Mac OS X 10.6.5, Safari 5 and iOS SDK 4.0.