The standard size of the console is 80 columns and 25 lines, which is too big if you want to work easily in console and don't even use a desktop environment (or use one but also prefer to do things in console rather than an X terminal). It will also look nicer when booting up the system.
To change the resolution and colour depth of the console you need to edit the /boot/grub/menu.lst file and add one parameter to the line containing the kernel to boot. On a Debian Lenny system, this should look something like:
title Debian GNU/Linux, kernel 2.6.24-1-686
kernel /boot/vmlinuz-2.6.24-1-686 root=/dev/hda1 ro quiet vga=791
The new parameter added is vga=791, which means a resolution of 1024x768 with a colour depth of 16 bits per pixel (65,536 colours). Some other VGA modes would be:
791 - 1024x768, 16 bit
792 - 1024x768, 24 bit
794 - 1280x1024, 16 bit
795 - 1280x1024, 24 bit
After you restart the system and boot in console mode (if a graphical desktop environment is loaded, just press CTRL+ALT+F1 to go into console mode, and CTRL+ALT+F7 to go back), you'll notice the resolution is now changed, and you can see more now than the standard 80 columns and 25 lines.
Updated: June 10, 2008 (Created: June 10, 2008)