Japan's solar sail Ikaros, is unfurled accelerating, and flying towards Venus.
Its guidance system has yet to be tested. But in all other respects its a great success.
Japan launched two Solar sails beck in 2004, plus the Americans and Russians have had a go, without much success. All have had unfurling problems due to the thin
silvered 'Mylar' involved.
Its unlikely that our sun would be strong enough to push a solar Sail beyond Jupiter?
But prehaps future guidance in that case could come from a Laser directed from the surface of Mars or an orbiting satellite?

http://www.space.com/news/solar-sail-exploration-hailed-100721.html

Awesome.

I suppose it should have no trouble getting past Jupiter - it can just keep on floating. Might be tricky coming back tho :P

Can't it be guided by radio like they're doing already?

I think the consensus is that beyond mars, solar intensity provides minimal force. But that doesn't mean the sail can only go to mars - it'll go as far as its velocity allows - build up enough speed in the inner solar system and you could escape the suns gravity all together. You just wouldn't accelerate much once you pass the orbit or mars.

The idea of using orbital lasers is an old one, and one which would work so long as you can find someone you trust to have multi-megawatt lasers in orbit.

Bryan