Android is technically open source. i suspect that Android will beat the iPhone OS in less than 2 years. but Apple has a good product and they continue to stay pretty close to cutting edge so they'll continue to sell like hotcakes.
Microsoft and Apple are not open source and don't claim to be open source. Apple uses some open source stuff (e.g., Safari is built from the webkit that is open source and Apple contributes back to the project). in that sense, Apple can probably claim open source, but the Mac OS and iPhone OS are very much proprietary. the iTunes Music Store is very much proprietary (e.g., you can't access it from a Blackberry). Apple is a for profit company so it doesn't make sense for them to be open source more than necessary. Apple still provides a better product than open source in most cases (e.g., only a geek might choose open source Ubuntu over the Mac OS for a laptop). however, Google's Android is open source and it's starting to look very, very good. Froyo is the 2.2 version of Android
and it is better than the iPhone OS in many regards and worse in some others. competition is good for all of us whether it comes from open source or not. most consumers don't think in open source and proprietary terms . . . they just want whichever product emerges as best.