Qt on Android
Does Qt support Android application ? if yes which version of android ?
Necessitas is the project that brings Qt to Android. All droids newer than 2.2 are supported, AFAIK. Necessitas was recently announced to become integrated with Qt Project, so in the future those 2 projects will release common packages.
then, when we have to expect for both in a common release?
Does Qt support iOS? if yes which version?
That's handled by another unofficial port - Qt4iOS.
As for Necessitas - sometime in 2013. There is a lot of work to be done, so I won't expect it to be too soon. But you can try Necessitas already - it's available as a SDK, setting it up is straightforward, and it works very well.