When I bought my Galaxy S, it was just the time when the phone's development picked up heavily. I started with the OCLF of Ryanza which made it faster than my brain could handle at first.
From there on I started to see what was happening around me. I saw the incredible Voodoo Project made by supercurio, which turned a good phone into a work of art, with its speed, color display and sound capabilities increased by several orders of magnitude.
And then I started following Darky. He was at first yet another theme/mod developer of the many, but then he started building something big. Passionate words, an insane update rhythm and a really cool look won me for his cause, and eventually for his tester team. His ROM grew so popular that he eventually has to create his own forum in order to manage the huge community built around it. I learned a lot of things as a tester, but what was most important is appreciating how Darky actually took a bunch of mostly clueless enthusiasts and turned them (us) into people able and willing to contribute in a fairly big measure, not because he taught us stuff directly, but because we all had to push ourselves to new reaches every day, in many aspects.
With that experience in mind, and now that a year is almost past, I can say that such knowledge, plus what I've learned, has made me not quite skilled as to be a developer (sorry, elspanish, I don't belong in that list
) but really understanding and appreciative of what developing, and particularly troubleshooting, entails beyond code.
The developers and teams that have worked seriously on our phone have been already mentioned, so I won't repeat names. All I want to say is, if you're young and eager and you're thinking about starting to develop stuff for a phone, be it the Xperia Play or any other, by all means give it a try: maybe you won't make the ultimate content for your platform (although you should aim there!), maybe you won't earn more than a couple thanks in your bar (which is not your objective anyways), but you will learn a great lot, and especially you will learn things after typing the last line of code, which are the really useful and enriching ones.
Lots of love, good luck, and start your engines.