Autocomplete search code needed PHP MySQL

Need fairly simple autocomplete code. Have searched and installed many varieties. Some work partially, some are too complex. What I'm not getting from all the online scripts is the ability to use the cursor key and enter. So how I'd like it to work is exactly like Google. Type a few characters (no delay, no minimum number of characters), and a list of matches appear. Then scroll down with down arrow key and upon ENTER, form is submitted. That last part is the part that none of the scripts are doing and I don't know enough javascript to do it. I will supply you with a simple demonstration MySQL file such as: Item# Product Name ------------------------------------------- AP416 - Apple iPhone4 16GB AP432 - Apple iPhone4 32GB etc. I type "ipho" and the product names show up. On ENTER, I want the Item # in an input field I can use later in my PHP script. Kind of like: <input type="text" name="product_name" id="autocomplete_box" /> <input type="hidden" name="item_number_select" id="upon_enter_put_item#_here" /> So as simple as possible. Minimal styling. jQuery use is ok. The MySQL part I can understand completely, so all I need is some sample code for that.