This is not a rumor!
It was officially announced that there will be a BRAND NEW Sailormoon Anime in Summer 2013! The original Japanese VAs for Moon and Tuxy seem to be reprising their roles (based on the conversation in the event). We don't have much more detail, a letter from Naoko said she hopes we like the new series and she's happy to be making it. She said she's overwhelmed at the support the series still has and it makes her happy. She didn't think she could do something new but now she's happy she can bring them back!
They said the audience is intended to be the original fans of the show. It will be like a "powered up" of the original story, aimed at the good girls (and boys!) who grew up with the show. TOEI is doing it.
There was something in the announcement about it being released worldwide but we don't know the details. We do not know what this means as far as a possible English dub/sub. We don't yet know when/how this will reach a US market.
The new theme song is being performed by Momoiro Clover Z. They performed "Z Otome Shinsou" - Z Girls War during the announcement but we don't know what the new opening is yet.
There is a translation of the video up on Miss Dream