the software equation
Andy Brice with a really interesting post which will tell you exactly how much you'll make on your software product.
On a side note, I didn't realize Andy had a blog. I'm really excited that he does, he's a top notch ISV.
On a second side note, Andy is perhaps a bit older than I expected him to be (just going by this photo). It's always fascinating to me how you build an image of someone in your head from virtual correspondence with them and they're almost always different than you imagined.