Auto complete??

I'm trying to work out the best way of going about the following project.

Basically, I have a SQL Server DB. It has a table with a group of category headings in a field.
I want to have a webpage with a search box on it and when the user types a word into it, I want to query the database and suggest possibilities to him or her.

It should work in a similar (but much more simple) way to this:
http://www.google.com/webhp?complete=1&hl=en

or

perhaps in a similar way to a web browsers URL bar when you type in a previously visited website.

I reckon I've got to combine client and server side code to do this. I'm pretty sure it's gonna be heavy on the server as well.
Has anyone got any good methods I could look into to get this done? I'm quite new to .NET having been a standard ASP man for a while.

Thank you in advance for any help.

use the Textbox's textchange trigger, when the user types something do an sql statement as such:

sql = "select sitename from popularsites where sitename like '" + txtSearch.text +"*'

then you need to populate the dropdown box with the results.