Change Console Resolution in Grub2

edit below file.

sudo vi /etc/default/grub

uncomment the setting "GRUB_GFXMODE=640x480", and change to the resolution what you want.

update grub and reboot.

sudo update-grub
sudo reboot

i test it on ubuntu 13.04, and it works.

Reference:

ubuntu 10.04 console resolution
Grub 2 and the VGA parameter