If you don't want to go into bios and change the boot order every time, you could also use grub to switch the sequence.

taken from http://www.novell.com/documentation/...l/ch07s04.html

7.4.1.3. Changing the Hard Disk Sequence

Some operating systems, such as Windows, can only start from the first hard disk. If you have such an operating system installed on a different hard disk, you can implement a logical change for the respective menu entry. However, this only works if the operating system accesses the hard disks by way of the BIOS when booting.

...
title windows
map (hd0) (hd1)
map (hd1) (hd0)
chainloader(hd1,0)+1
...

In this example, Windows is started from the second hard disk. For this purpose, the logical sequence of the hard disks is changed with map. This change does not affect the logic within the GRUB menu file. You still need to specify the second hard disk for chainloader.