AJAX search box

I have a? database with 10,000 products in the database and i need a very user friendly interface for users to find an item. I want the user to be able to type 'sd' and immediately all the items with those characters to show up below the box with a count of how many items match. Then as the user enters each character, like 'sd7' it will refine the results more. Finally, when they enter 'sd700' there will be few results. But speed is a very critical issue, and we need to make sure that the results appear instantaneously, without a postback. There are? 5 columns they search by: NAME, SKU, UPC, MANUFACTURERCODE, ASIN I want then to be able to type any part of? these fields. The only exception is the UPC, that has to be a whole string. The reason for this is because it will be inputted via a scanner typically. code must be written in vb.net and data is in SQL server 2000.