I have noticed some developers picking up new skills and moving from one platform to the other? How do they do it? How do they justify for the lack of experience in the said platform they get the job?
Is it based on relevance to their previous experience? do they get certified in the target platform and work at a junior level accepting a pay cut? is it simpler if you are into contracting/consulting? Or is it simply a matter of projecting the resume correctly?
Most likely it is a result of circumstances. In these touch economic times being able to move outside your comfort zones is crucial
Actually, a lot of seemingly different platforms are really very similar, if you understand what goes on "under the hood," as it were. Though I've barely touched a Microsoft platform for well over a decade, for example, I have little difficulty developing things there because deep knowledge of computer systems in general is quite transferable.
For me, moving from LAMP to .Net was a work necessity. The consulting company I work for needed a PHP guy right away which is how I got in, but that project completed abruptly and they did not have an PHP work on the horizon.
In the closing weeks of the PHP project, I took an online O'Reilly course in C# and worked closely with a more experienced developer on a Windows application for the same client. Once the PHP gig completed I was able to start right away on a .Net project and I've had .Net clients ever since.
The key for me was flexibility. I let my employer know immediately that I was interested in different technologies and platforms and have taken the initiative by requesting access to courses and taking advantage of our yearly book allowance to explore different areas. When opportunities arise for investigating new directions like Mobility (PDAs, specialty devices and tablets) I jumped at the chance.
If your employer doesn't have policies which promote this type of self-directed expansion, then try to build a type of application you are familiar with in a new platform. Once you have you have a decent grasp of the tech, get involved with open source projects in your target platform and look for paid outside opportunities (i.e. Craigslist, elance, etc.) while you are still learning.
I really haven't seen a lot of reluctance on anybody's part to put developers on platforms that are new to them. Changes in computer language tend to be far more worrisome to managers than platform changes.