Smart phone OS showdown: iPhone vs Android vs Palm Pre

By far the most open is Android. It's an open-source project, which means anyone can take the operating system and modify it to run on their handset, or even a netbook. In fact, we'll wager it'll end up in cars, sat-nav systems and all manner of other things too.

The webOS and iPhone OS rank about the same in terms of openness. Like Android, webOS is Linux-based, with OS X being derived from BSD, which is a Unix variant. So while both are built on historically quite open platforms, they're not themselves open for developers or for redistribution.

This means if you want to develop for either, you must pay either Apple or Palm to do so. Palm charges $99 (£60) for entrance into its developer programme and $50 (£30) per app submitted to the store. Apple charges $99 per year and both companies take 30 per cent of your app revenues, if you opt to charge.

Google charges a one-off fee of $25 (£15) to developers. It's possible to develop apps and distribute them yourself, although you won't be listed in the Android Market if you do that.