It’s January 3rd, and that means two things. Vacation time is over (sorry, kids of the world). And, it’s time for me to put on my thinking cap and proclaim 5 casual gaming trends you’ll see in the upcoming year. That way, in the small event they happen, I’ll be proclaimed a genius!

Every day this week, I’ll make a casual game prediction that will either astound you or make your shake your head.

Today’s prediction: Apple and iOS eclipses Microsoft and Windows to become the #1 platform to developer casual games for.

For the longest time, game developers created games for the PC first and released a Mac version months later (or never). In 2011, there will be a role-reversal. The reason is iTunes.

On January 6 (just 3 days from now), Apple will release Mac software in iTunes. By itself this will not have a big impact at first since there are far more PC running Windows than Mac’s in the world.

From a developer’s standpoint, however, this is huge. iTunes pays out 70% of revenues to game developers and keeps only 30%, which is essentially the opposite of what game developers earn by selling a PC game through digital distribution or retail.

Furthermore, game developers can set the price with Apple (they can’t with PC games) and since games are developed in Objective-C, it is relatively easy to develop a game for both the Mac and iPad at the same time, and just a little more challenging to do so also with the iPhone (it’s more a graphics than a coding issue).

When you combine the facts that developers can earn more twice as much per Mac than PC game unit, can set their price, and can develop games for Mac, iPad, and iPhone and sell on iTunes on the same time, the answer is clear.

The PC market may be bigger, but the market opportunity will be larger for game developers on Apple’s iOS platforms. For the first time ever, games will come out on the Mac before the PC.

That is, unless Microsoft creates an iTunes competitor of their own (think Zune for the PC).