What work has been done on cross-platform mobile development?
Have any well-documented or open source projects targeted iPhone, Blackberry, and Android? Are there other platforms which are better-suited to such an endeavor? Note that I am particularly asking about client-side software, not web apps, though any information about the difficulties of using web apps across multiple mobile platforms is also interesting.
What work has been done on cross-platform mobile development?
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Have any well-documented or open source projects targeted iPhone, Blackberry, and Android? Are there other platforms which are better-suited to such an endeavor? Note that I am particularly asking about client-side software, not web apps, though any information about the difficulties of using web apps across multiple mobile platforms is also interesting.