Although I participate in SETI@home, I have less faith that we will detect electromagnetic radiation in the form of communication. If they are out there and near enough to see us, they are likely more advanced, and can point a signal straight at us. EM is not an efficient method to communicate between star systems, and I'd guess we haven't found the best method yet. There may be some way we can take advantage of quantum entanglement that we haven't found yet, which might allow for faster-than-light communication. Or, maybe something else entirely. My guess is that we are in the middle of a conversation, but we aren't able to hear it yet. As for when we will, who knows. Maybe 30-40 years? Or maybe our robot overlords will take care of that in their own time. :)