I don't have a crystal ball but I think Android has a lot of potential. There was an analyst's report recently that predicted Android phone sales would surpass iPhone sales by 2012. I learned how to program both (see my
series of articles on that), but my focus is on Android.
I do have a paid application on the Market (called
Re-Translate) but it was mostly intended as a learning experience rather than a money maker. Which is just as well since it hasn't made much money.
Currently I reduced the price to $0 to drum up some users and good reviews. I have another
series on that if you want to follow along.
Mark Murphy has also started a series about the Market for AndroidGuys.