Tim Anderson says that Nokia's Elop fears mobile duopoly. He tries to make sense of it: "This is not good for Nokia, though it might be 'the least bad of all the poor choices facing Nokia'." He also talks about how Nokia killed off the Qt devs within the company after saying they were the future. Oy.
http://www.itwriting.com/blog/3887-nokias-elop-fears-mobile-duopoly-but-it-is-already-here.html
But then I read Loic Le Meur on the "new nightmare of developers and brands" that all these platform ecosystems are creating, and I can only imagine how devs might be tearing their eyes out of their sockets:
http://www.loiclemeur.com/english/2011/02/the-new-nightmare-of-developers-and-brands.html
You need to be on all the above platforms stores, of course. But wait, there is more. You need to submit and manage your app to the mobile carrier app stores, they all have one. That's only a start, wait until the manufacturers themselves, the Samsung, Dell, HP and Sony have theirs, HP has one with the Palm acquisition... Even Amazon has an store for applications. Bonus startup idea of the day: create a service to help register and manage my app in all those stores in all languages, I can be your first customer.