I'm beginning to look around for reliable and, well, free non-authenticated web services for doing financial analysis. Here's one that provides a free symbol lookup: WebserviceX.net Stock Quote.

(I got pretty addicted to the XML-based data that Amazon provides for helping to fill in the details on some of my media.)

And, it would appear, that it doesn't take much digging around the web to find service after service for stock quotes. E.g., SwanandMokashi.com - Our web services has another one, powered by Yahoo! financial data.

I think comes down to looking at this point at the various response messages and which has what needs to be tracked.