It's true that the SEC makes this data available free of charge, but it's typically not useful without a lot of extra processing. XBRL(http://en.wikipedia.org/wiki/XBRL) is a standard of sorts, but there seems to be no enforcement of how it's used across different companies' filings (or even across multiple filings from the same company), and many critical pieces of information are filed under e.g. company-specific extensions. It's definitely a pain working with the data in any meaningful way.
FWIW, www.downside.com had a hard time reading the latest filings for AAPL, the only one I tried. Visiting http://www.downside.com/cgi/testfinancialsextract.cgi?url=ht... threw an error "ERROR: SGML Parse error: EXCEPTION reading from net: The filing is bigger than the maximum allowed size of 5000000 bytes. at EDGAR/netutil.pm line 75."
FWIW, www.downside.com had a hard time reading the latest filings for AAPL, the only one I tried. Visiting http://www.downside.com/cgi/testfinancialsextract.cgi?url=ht... threw an error "ERROR: SGML Parse error: EXCEPTION reading from net: The filing is bigger than the maximum allowed size of 5000000 bytes. at EDGAR/netutil.pm line 75."