We're still not sold on the idea of watching TV shows on tiny handheld screens. Then again, there are worse ways to kill your time on a crowded BART train than watching the latest "Lost'' episode on an iPod. Regardless, someone believes mobile TV has a big future, because Emeryville-based MobiTV has closed a Series-C financing with lead investor Oak Investment Partners. The amount: $70 million, which will be used to "fuel the Company's rapid expansion in response to the overwhelming demand for its mobile television and radio service across international markets.'' Bandel Carano of Oak Investment joins the board. MobiTV provides mobile TV and digital radio service for cellular, WiFi and broadband enabled devices. If you're on Sprint, Cingular and Alltel, you might have used the service.