<p>What is a good mobile programming platform to go with for a <code>c++</code> developer? </p>

<p>Is learning <code>android</code> a good option?</p>

Java ME
will give you the widest choice of deployment options and market share, because most mobile phones support it.  Going from C++ to Java is quite easy, since Java has fewer gotchas than C++.  As a positive side effect you will also get to learn Java on a platform whose footprint is a lot smaller and manageable than
Java SE
.