I think what is likely to happen is that once large numbers of cores (say 8+) become commonplace, then we'll see development of applications that take advantage of parallelism that were not considered viable in a single-threaded world.
I cant think of specific examples, but consider what happened when 3D accelerators became common. Games at the time (think Doom) were bound by the speed of their software rendering code. Having highly-detailed 3D models, simulating reflection/refraction and per-pixel lighting were not even considered. Nowadays everyone does it.
So unless your current apps are highly CPU-bound, I would not worry about parallelising them. If you find you have heaps of CPU power via multiple cores, then look at ways to exploit it in new projects.
