I just went through the same scenario that you want to do. You can do this very easily.
There are just two important steps that you MUST do.
First- Create a different folder for the installation of O2K. (There is NO problem for it to be on the same partition as O97, but it must be in a different folder)
Second- During the installation you will be asked if you wish to keep the previous versions of the different office applications. Make sure you say yes to keep the previous versions.
That's all there is to that. There is documentation on the CD to explain this scenario. You can modify up the "Office short cut bar" so one will be O2K and one will be O97.
The only real difference between the two suites is the Access applications. Access is not compatible between the two versions, whereby, Word and Excel integrate with no problem.
Good Luck. Rich