Third party support is still rather weak (the only game I'm planning to get in the near future is Little King's Story, which has been pushed back to early next year), but that's because 3rd parties are still making the transition from ps3/360 to Wii. The games will arrive aplenty next year.
Of course, third parties won't abandon the ps3/360 either. "Hardcore" games generally sell better on either the ps3 or 360 than they do on the Wii, so a multiplatform ps3/360 game is the way to go at the moment. Despite added development costs, the added sales of releasing on two consoles plus an extra $10 per game sold (though the devs probably get less than $5 of that) will ensure third party support for the ps3/360 for quite some time.
Of course, this is an issue of making a game for the Wii vs ps3/360. More and more publishers could begin making games for all three, much like the Call of Duty 5.
