Heavens-above.com is a website I found about a year ago, if you put in your location, it will show details of when you can see the International space station (ISS) in the night-sky.

You don’t need to register, just input your location (or select from their database), then on the homepage click where it says “10 day predictions for: ISS”

Look down the Starts and the Date columns for a time that is suitable, and then check the Magnitude (Mag column). The lower the number, the brighter the ISS will appear.
Once you’ve found a good date, make a note of the start time. The ISS will move across the sky from details in the Starts column to the Ends column, passing through the Max alt. column.  For example, if the starts, ends, and max alt columns say W, S, E; it will go from West to east. The altitude describes how high you need to look up.

If that is not easy to understand then don’t worry, just pick a good magnitude and on a clear night go outside at the start time and look around for a few minutes until you see a light that looks like a star moving about the same speed as a plane.

The times are accurate, so as it only lasts a maximum of a few minutes, you need to be outside looking up on-time. I use MyPhoneExplorer to sync the clock on my K800i via ntp.

The same website can be used to get viewing times of Iridium flares, and any upcoming Space shuttle mission (they are listed as STS-xxx) on the homepage.

Iridium Flare - Click for a larger image