Mobile World Congress is now approaching the halfway point in Barcelona, and there’s been a lot of exciting announcements, revelations and, well, general cool stuff.

The main talking point seems to be Google’s stall at the event. Actually, ‘stall’ serves as a massive injustice to Google on this occasion, considering it has a huge slide and an army of giant android robots keeping a watchful eye over proceedings. What’s wrong with good-old fashioned branded pens and notepads?

Anyway, Google’s Android certainly seems to be stealing the show so far, with everyone talking about the mass of Android handsets and tablets not only available at the moment, but on the horizon.

The first HTC Android tablet, the Flyer, is on the way, as well as sequels to the Desire and Wildfire handsets.

But cool devices aside, these developments all point towards a very big year for apps.

Apple recently announced its ten billionth app download, which is a remarkable milestone to reach. But with Google recently outgunning Nokia to number one spot in the smartphone market, in terms of number of units shipped, the demand of Android apps is only going to go up.

In fact, some estimates are already suggesting there could be over seventeen billion app downloads in 2011, across Apple, Android and Blackberry platforms. Roughly double the number in 2010.

And Android is likely to steal the lion’s share of the downloads given its rise to the top of the mobile platform tree.

This is fantastic news for app developers, given that a whopping $15.1 billion is predicted to be spent on apps in 2011, tripling the figure in 2010. So if you’ve thus far focused your efforts on developing for Apple or Nokia, now could be a good time to switch allegiance and hone your Android developing skills. There’s a lot of money to be made!