A small separation camera has detached from IKAROS and has taken a picture of the entire craft with sail unfurled. Check it out:
Read the JAXA press release here.
Unlike Earth-bound vehicles, spacecraft don't have to keep their engines going to keep moving. And since propellant is very expensive to lift into space, engineers work out clever ways to economize, so they can do a lot with a little (check out this great article on extending the Cassini mission). Conventional rockets get a lot of acceleration all at once, but as soon as the engine is turned off, they just cruise through space at a constant rate, more or less.
The solar sail is sort of like the tortoise racing the hare. It starts off very slow, with the photons bouncing off the sail and creating a small amount of thrust. But that thrust is constant, so over time the craft continues to accelerate. It can pick up incredible speed and, if it is demonstrated to be successful, could significantly reduce the time it takes to reach neighboring worlds. And for farther destinations, the craft could reach higher speeds.
I'd love to see this technology catch on. So let's hope IKAROS has got the right stuff.