Currently, the full 113 Optimus is not available but should be by the end of the year. In the meantime, a much smaller 3-key version (which employs OLED screens) called Optimus mini three is on the market. The 113 key version of the Optimus should start around $200 – not cheap for a keyboard, but extremely handy.
Update (3/28/2007): After talking to Artemy Lebedev on CeBIT 2007 we can now confirm a much higher price for the keyboard (now called Optimus Maximus). More details from on our CeBIT 2007 coverage. Updated price: $1500.