For information on how to download Debian GNU/Linux from the Internet
or from whom official Debian CDs can be purchased, see the
distribution web page.
The list of Debian mirrors
contains a full set of official Debian
mirrors, so you can easily find the nearest one.
Debian can be upgraded after installation very easily. The
installation procedure will help set up the system so that you can
make those upgrades once installation is complete, if need be.