Nintendo announced that Pokemon Diamond and Pearl have sold 10 million units worldwide. That's one for every dollar in this year's Publisher's Clearinghouse sweepstakes. The games have sold a collective 5.2 million copies in Japan, with the US making up most of the rest. Diamond and Pearl just came out in Europe on the 27th, so expect this number to continue climbing.
Don't expect the formula for Pokemon games to change any time soon. At this point, that would be harming the economy of a small nation, composed entirely of Pokemon game cartridges.