However I believe Android won't attract many developers/companies as long as there is no decent way for selling custom software.
*shrug*
The PC did quite fine without an iTunes-style distribution mechanism. OS X does quite fine without an iTunes-style distribution mechanism. Linux perhaps comes closest to having an iTunes-style distribution mechanism (the distro and package managers).
In other words, while having an iTunes-style distribution mechanism is handy, if customer demand is there, apps will find a way to get distributed.
I'd like to know if there is a distribution platform for Android software planned/available similar to Apple's ITunes.
Even better! Android supports several such markets (Android Market, SlideME, AndAppStore, Handango, Voeveo, etc.), and you can distribute outside of a market (e.g., download from a Web site). There is no monopoly control over application distribution like some platforms have.