Hoshi no Koe, Kono Danshi, Uchuujin to Tatakaemasu. Recommendations
Art in both OVAs is similar. They also share the same feeling and in both a cell phone plays an importand role. Only difference is that Kono Danshi, Uchuujin to Tatakaemasu is labeled as (very light) shounen ai and Voices of a Distand Star is normal romance.