PS - There's lots of Windows software that is open source too... Mozilla, for for example.
And just a whole list of links you could link on and read about
:
http://www.groklaw.net/index.php - Details about the SCO lawsuit against Linux and Linux vendors. SCO claims to have all sorts of legal claims to Linux, most everyone feels it's bunk.
http://fedora.redhat.com - The Linux distribution I personally use.
http://www.linux.org - General Linux Info
http://www.mysql.com - The premier database server for open source, most likely used by TPWWW too. Just notice how many Fortune 500 companies rely on this software.
http://www.openoffice.org - An Office suite, similar to M$ Office. This runs in Linux & Windows.