Importing Yahoo Finance Stock Data

I've got a project that I think would benefit from the use of being able to import and update fields from an external source like XML. In this case Stock information. I'm pretty new to importing XML data and couldn't get anything to work for me. I suppose I just don't fully understand the mechanics of the process.

I did some research and found that you can query Yahoo Finance and it will return XML data: 

http://thesimplesynthesis.com/article/finance-apis

Is it possible to update one record at a time, and also update all the records at once? What's needed to do this? Is there a base template to start from? How are fields linked? XML template file?

If there are any tutorials or guides on this or any supporting information on how to accomplish this would be greatly appreciated.

Thanks!