The other side of the universe is on the other side of a black hole.
Since a black hole is not a hole at all, but rather just a point in space where light can not escape (http://mattforte.hubpages.com/bha/hub/Why-Does-Lig... ), then it doesn't *lead* somewhere, in the sense that you seem to be thinking.
This should simplify things:
Pick up a beach ball.
Hang the beach ball somewhere in your room, from a string.
This beach ball is a black hole, your room is the universe. What's on the other side of the beach ball? More universe.