There is suprisingly little information on their site, considering it is due for release on June 30th (even that date isn't on their site, but on their distributor's product page.) The cost will be $199.
I imagine that developer information will come during/after Google IO this week, as right now, there are just six marketing bullet points on the site.
The distributor's page does have a little more information:
Add your own thread to the watch for special functions
Use the Meta Watch low-power application framework
No need to open the watch for in-circuit debugging
Uses TI SPI-BY-Wire
Leverage the Bluetooth radio and remote protocol for communication
Sample code which is an Open Source Android SDK project demonstrating watch connectivity to an Android phone. The project demonstrates watch idle screen use as well as notifications for: CallerID, SMS messages, alarms, calendar events, music control, email and IM.
Sorry I should have linked in my original comment, that's the page I was looking at to get the launch date and the extra SDK information. It's still very scarce, though.
I imagine that developer information will come during/after Google IO this week, as right now, there are just six marketing bullet points on the site.
The distributor's page does have a little more information: