National Geographic has posted a great zoomable map
detailing the first fifty years of the conquest, sorry, exploration, of the Solar System by robots. If you want to expand your mind, check out the graphic at the bottom, which shows where long-range probes are right now. New Horizons, on its way to Pluto, has recently crossed the orbit of Saturn. Much
further out, past the orbit of Pluto and the Kuiper Belt, are Pioneers 10 and 11 and the two Voyagers. Voyager 1 is 10 billion miles from the Sun, 10 times more distant than New Horizons's present position: it's the most distant man-made object, and it's still, just, inside the Solar System. Space is big.
(Link via Universe Today