You can configure GRUB (like menu editing, pause length etc.) with the help of file /boot/grub/menu.lst. But there are a little better method with the help of GUI.
Startup Manager is a graphical tool for configuring GRUB, Ubuntu splashscreen etc.
You can download .deb file from here (62.8Kb):
(double click for install)
And now you have a new item StartUp-Manager in the System -> Administration menu.