I use UNetbootin, which copies the Debian installer to a USB flash drive, and makes it bootable. Then you just boot from the USB flash drive, do normal Debian setup, and it downloads everything it needs to do a full install over the internet. There are versions of UNetbootin that run on Windows or Linux for creating the bootable USB flash drive.
You can do it manually following the instructions in the Debian installation manual, but I find Unetbootin far more convenient. http://unetbootin.sourceforge.net/ -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org