But the iPhone market is the biggest at the moment
No, it's not.http://bit.ly/lABLvH
January 10, 2011, about US market: 26% had an Android-based phone, ComScore reported Friday. Third-place Apple followed with a 25% share and Research In Motion, maker of the BlackBerry, led the pack with a 33.5% sharehttp://bit.ly/fzPLiP
February 2nd, 2011
Google's Android market share was 32.9% in Q4 of 2010, passing the iPhone at 30.6%. Microsoft actually sold fewer units than last year. Nokia was relegated to the "others" category. In IT Blogwatch, bloggers are fascinated by Android's 615% annual growth.
April 4th, 2011. A broader look at Apple vs Android markethttp://read.bi/hGbEre
And this page http://bit.ly/l2wEvZ
Had this interesting, easily readable chart just a month ago, April 5thhttp://bit.ly/kaUQc6
Just from the first ten result when googling 'Marketshare iPhone Android' and it's Dutch equivalent.
Could probably dig a bit deeper, but I'd feel like beating a dead horse ;)
ETA: I don't think the discussion about the platforms is off-topic at all really. Assuming there isn't a huge development team available, choices will have to be made about which part of the market you want to reach first. Marketshare, stability, security, it will all play a part in that decision. Or at least it should.