downloadable stock price history

Hey, I googled stock price history and ran across your page.  Pretty cool.  I am interested in finding out how Yahoo and the like come across their stock price information.  To be specific I have an interest in stocks and wanted to experiment with some thoughts I had after reading a book on stocks.  It dealt primarily on chart analysis.  I consider myself fairly decent with excel and wanted to see if I could materialize my ideas.  What I'm looking for is a history on any given stock looking back upto a year, dumping that information into a spreadsheet and then running some formulas on that data.  And then apply this to a rather large sample of stocks with minmal effort on my part maybe just a print out each morning meeting specified criteria.

Is there a fee to obtain this information?  Is it public domain?

Thanks again for any assistance you might be able to give.