It's also a hard question to answer, because it depends on app popularity, price, complexity of the app, etc. For my next project, I am planning to roll over iPhone and Android nearly simultaneously, so I look forward to answering that question in a blog post, at least in a relative way.
At least that's how it was last year when I 'used' to do iPhone dev..
Apple only gives you access to the address book, very annoying.
Would love to get more access, to calendar, calls data etc...
As I'd be perfectly willing to do the minimal work of submitting your app for a small portion of the proceeds.
Dealing with international tax law probably makes this not worth it for a small company, particularly as a side business, but it's a thought...
However, with 15 some odd phones releasing in the near future, if you're doing mobile development, you have to be putting more focus on Android.