Providing the night sky is clear, the International Space Station is visible from as early as 21:30 for the next couple of weeks. It only takes a couple of minutes to across the sky, so you need to be ready for it! For exact times, see the Heaven Above website.
If your astronavigation skills are anything like mine, I highly recommend Stellarium to help find your way around the night sky. It is available for Mac OS X, Linux and Windows.
Here are my better pics from Friday night,