It would be absolutely stupid to think of outselves as the only intellegent (?) lifeforms in the universe, as to when I think we will discover any other life I have no idea, could be today could be never!
Should humans transmit a beacon for others to find? What do you think TV is? Its been going for almost 80 years (excuse my ignorance if I'm wrong!) that's quite a volume covered already! Although with advances in transmission technology/techniques we're venting less and less signal into space, and it's becoming harder and harder to understand (decode).