smart website search

Hi

I'm currenrtky working on a site that needs a search functionality that works like ebay, amazon etc and has the ability to pick up small mis-spellings and also the ability to show search history as the user types.

Does anyone know of a plugin or open source code that I can use/buy?

The mis-spellings feature is known as "stemming" - Sphider does that - here's the link: http://www.sphider.eu/