A multi-OS system requires more than merely creating several partitions and installing two or more Operating Systems.
As mentioned in my previous post, get Partition Magic 8.0 with Boot magic included. If you want to cut costs a bit, get PM 6.0, which should be available cheap now that 8.0 is the latest version. At $60 to $70 (American), 8.0 is a good buy, and somebody might be selling it cheaper at a computer flea market. 6.0 should be available for no more than $30 to $40 and will probably do the job.
The cleanest way to do this job is to have multiple primary partitions on your first disk. Only one is visible at at time. Boot Magic hides the ones you do not want and boots the partition with the OS you select.
PM can resize and move existing partions without losing any data. This is important, because you never get the partition sizes right the first time you set up a Multiple OS system. Furthermore, it is quite likely that you will find a need for an extra partition 6 months later. PM will allow you to shrink one or more existing partitions, move them, and provide space for the extra partition. All wihout losing data in your existing partitions. Even if you do not run a multi-OS syustem, PM is a handy utility.
I think an application called System Commander is also a reasonable choice, but PowerQuest has been doing this for at least ten years with Partion Magic, and they are likely to be the best. The various dual boot options available, are an inferior method. Dinosaur from prehistoric mainframe era
Eschew obfuscation!
If one hundred million people believe a foolish idea, it is still a foolish idea!