I just wrote about Google's rumored mobile phone, the Google Phone, running on Linux. Now, if this is true and it is based on Trolltech's Greenphone, then you better start learning how to develop software for the phone. The best starting point is a tutorial published by linux journal.
Now, if only Apple releases the same SDK for their Mac OS X-based iPhones, then it will be a very interesting battle. At the end, the consumers will win. Now, isn't that nice? :)