Running more than one Microsoft server product on the same machine is always tricky. If you really do not need them on the same machine you should consider running all these machines as VMs.
We usually advise our customers to use virtual infrastructure instead of physical machines. VMs are cheaper to implement and easier to manage. Our usual infrastructure setup is one (or more) physical machines and storage cluster. On physical machines we are running every Microsoft server product (CRM, MOSS, PerformancePoint, Project Server) on a single machine.
If virtual machine approach is not acceptable, and you really need to run MOSS and Project server on the same machine, take a look at following article.