Question: what software environments are commonly found on both PCs and mobile phones? (and maybe other devices like games consoles, TVs/set-tops etc)
Symbian & Brew are mobile-only, Linux will get there eventually but isn't always open to developers, all the other mobile "on device application" clients don't have much of a PC story.
But almost every browser has Flash, and increasing number of handsets have Flash Lite (eg many Symbian devices, plus also an increasing number of featurephones).
Now add in James Enck's blog comments about Adobe's interest in VoIP
And now add in 2 million Flash designers who could do cool things with an underlying easy-to-extend VoIP/SIP/IMS platform on both PCs and phones.
And finally, remember how many of the problems around FMC and new mobile services relate to complexities in user interface design.
Only remaining question..... are they going to be operator-centric, or "developer-neutral"?