Today, Google launched Google Website Optimizer as a service to enable website owners to test different landing pages and determine the pages with the best conversion rates.

Conversions can be sales, downloads, newsletter subscriptions, really any on-site activity that you would like to track.

Google Website Optimizer is integrated as a free service into Google Adwords. Website owners will need a Google Adwords account to make use of the optimizer.

By adding a few javascripts to your landing page, Google will automatically create and track different variations of Headings, photos, quotes and paragraphs to determine the highest converting combination.

For more information, Google has an overview video and video user guide available.