The most up-to-date elements for satellite tracking from US Space Command: http://www.space-track.org
The following files are distributed by T.S.Kelso http://www.celestrak.com
To download: shift button and click on link or click the right mouse button and choose "Save as..."
The following links belongs to Nasa Human Spaceflight http://www.spaceflight.nasa.gov/spacenews/index.html
Invaluable to predict ISS and Space Shuttle orbital positions during space manoeuvres