announced a new feature that will become part of its Steam service called Steam Cloud, which will allow Steam users to store things like their keyboard and mouse settings online on one of Valve's servers.
This is a great feature for those that have a Steam account and play the games away from their home computer, say, for example, in an Internet cafe or over at a friend's house. It will also be possible to store things like paint tags for Counter Strike.
The settings will be implemented automatically as you launch the game on a second system and any changes made on this system will be automatically saved to the Steam Cloud. The new features will be available for all companies that use Steam as their game delivery platform free of charge.
Steam Cloud will go live with the demo of Left 4 Dead, which will launch on Steam later this week, with the full game following on the 18th of November. Valve is set to add support for Steam Cloud of all of its already released Steam compatible titles, although this might take some time to implement.
More details here