Telecom Italia supposedly announced their ebookstore today, but I'm having trouble getting specific details like number of titles, ereader price and availability, and format support.
Right now it appears to be in a private beta at a festival, Festivaletteratura 2010. They're using Wifi devices at the festival, but according to their website they will be selling 3G equipped ereaders when the store is officially launched.
In case you were wondering, yes the ereader pictured is the same hardware as the Thalia Oyo.
Update: New reports indicate that Sagem will be providing the ereader for Telecom Italia. I've covered them before (and I even have a video of their ereader).