With the "many universes" answer in the poll I meant that the Big Bang was not a unique event, just from the consideration that if it can happen once, it can also happen infinitely often. In that case, the other Big Bangs happened befor our Big Bang, after our Big Bang, and also possibly at the same time. The question of "When" and "Where" of the other universes does not make much sense here as they are outside our space and time (and aren't in a "hyperspace" either).

However, the Andrej Linde interpretation of string theory postulates that not only one but many universes were created by the Big Bang, and are still created by local hyperinflation. In that case the question of the "where" and "when" can be answered more precisely when we manage to put the string theory together - probably within the next 40 years.

http://www.world-science.net/exclusives/060330_multiversefrm.htm

In both cases you won't be able to visit the other universes. They are separated from ours by event horizons.