How can I boot between 3 different operating systems?

At home I have Windows7 and WinXP in a dual boot situation. I suppose when I installed Win7 it installed a boot loader, so now I can choose which os to load. I would like to take an Acronis image of my office WinXP system and install it on my home pc on a separate partition and boot to it occassionally. After I put this office system on my home pc, how can I boot between the three systems?