High resolution Terminal (tty)

To change the resolution of your tty's, just append the words "vga=XXX" to the kernel line of your /boot/grub/menu.lst

      colour          depth   | 640x480  800x600  1024x768 1280x1024
      256             (8bit)  |  769      771       773      775
      32000           (15bit) |  784      787       790      793
      65000           (16bit) |  785      788       791      794
      16.7 Mill.      (24bit) |  786      789       792      795

example:

cat /boot/grub/menu.lst
...
title Debian GNU/Linux, kernel 2.6.26-2-686
root (hd0,0)
kernel /boot/vmlinuz-2.6.26-2-686 root=/dev/sda1 ro vga=791
initrd /boot/initrd.img-2.6.26-2-686
...

If you want to go deeper, search for frame buffer
Thanks to Themis and Michalis