Dual booting windows is easy. Make 2 partitions and give space to the windows partiton with gbs of choice. remember you have to have an intel mac to do this. Then reboot and choose the windows DVD, install it on the partition (you will know where to install it if you remember how many GB you gave the windows partition) then after install. Install bootcamp drivers then woola
with dual boot, you can use Parallels Desktop, Vmware Fusion or Boot camp. With triple booth, i am not quite sure if these virtualization software can handle that. Maybe you can check this out. And Yes you need an Intel Based Mac to do this.