RealNetworks continues to add to its mobile business, saying today that it paid $9 million in cash for an arm of Sony that offers music downloads and streams to wireless subscribers in eight European countries.

This follows Real's September acquisition of South Korean company WiderThan, which helps carriers sell music downloads and ringback tones.

I've asked the question before and will ask it again. After years of tough battles on the PC and Web, is RealNetworks on the verge of becoming a wireless company?

See our news story here.