Google's Website Optimizer provides an easy method for Web usability testing. The program permits you to experiment with different template variations until you find the one that produces the most conversions.
Getting started with a website optimizer
The website optimizer will ask you for specific information, such as:
Who needs template variation testing?
Anyone who wants to improve conversions can use template variation testing, but E-commerce site designers who want to choose between different images or copy will benefit the most.