I'm currently taking a course with Professor Uzi Vishkin a parallel computing visionary. His approach to programming mutli-cores is quite impressive. The system he has devised, while complex under the hood - is relatively simple to the programmer.

Essentially, in Professor Vishkin's model the program alternates between parallel and serial mode as needed. Under the hood, it is determined what processors handle what threads etc.

Have a look at: http://www.umiacs.umd.edu/~vishkin/XMT/index.shtml.

Parallel will be to serial, what the car was to the horse.