The reported Android based phone will be manufactured by HTC, and implies that it will support both GSM and CDMA network. But 3G communication will only supports the CDMA network (EV-DO).
So stay tune.
[Updated: September 19, 2008]
Thanks to the reader, Travis, for pointing out my mistake. I stand corrected that it is T-Mobile in the US who will be releasing the first Google Android phone by HTC in early October to the general public.