An easy way to take advantage of a dual-processor system would be to formulate your problem in a way that allows you to split it up into two (or more) parts. Fork off a second process (that will hopefully be put on the second CPU by the OS's scheduler), let both of them crunch away on their parts of the problem, and use the standard IPC facilities to communicate between the processes.

If you expect to do your crunching on bigger iron, parallelize your problem more (it's always a good idea to do so, anyway), and use MPI from the beginning - that will save you a lot of hassle later on.