nextwebgen.com

Google has released a AJAX Search API which allows you to embed a search control that displays the results inside of the page using AJAX requests. You can sign up here.

“The Google AJAX Search API lets you embed Google Search in your personal web pages. A single AJAX Search API key is valid within a single directory on your web server, including any subdirectories. The Google AJAX Search API is an experimental API that lets you integrate a dynamic Google search module into your web pages so your users can mash up Google search results with other content on your site or add search results clippings to their own content.”