A few independent sources have confirmed that Nvidia's dual chip will launch in early March. This is a few weeks later than originally planned. Nvidia decided to push this card into March and it looks like it might launch in the week following CeBIT.
The Geforce 9600GT launches on February 19th. The Geforce 9800GX2 is reported to be hot, as two chips can dissipate a lot of heat, but this shouldn’t stop the card from having top notch performance.