You might have seen the news that Google Finance now uses Google Suggest to decipher company names and ticker symbols as you type.

In this post:
http://www.resourceshelf.com/2006/07/20/results-before-clicking-the-search-button/

we take a look at several other tools that offer this type of techology including LookAhead, a service that licenses its technology to any webmaster or site owner.

They also have a demo of something similar to what Google is offering with info for more than 30,000 company names and ticker symbols. I talked to the developer of LookAhead and he said he was able to build this tool in about 15 minutes.
See:
http://lookahead.surfwax.com/examples/yf/

They also have a cool blog search demo.