Siemens has made available a firmware (version 06) update for the SX1 which you can download and install yourself. Additionally some free software for the phone is also available - this is a result of Siemens liscensing software from Symbianware. Currently available are Astronix, Powerball, Powerlock and Full Screen Caller, and there's more on the way too.

AstroNix
AstroNix - the high speed action experience offers you tremendous graphics, impressive sounds and a fast gameplay.

PowerBall
PowerBall is a unique and innovative mix of arcade classics with realistic ball physics and addictive game play.

Full Screen Caller
Do you want to see more cool details of the people who are calling you? Well, then please use the Full Screen Caller and your wish will be satisfied!

PowerLock
PowerLock is a convenient and informative screensaver that looks great while protecting your screen!

Both the firmware and the free software are available through My-Siemens (you'll need to sign up for a free My-Siemens account).