We saw the hints that phone support was going to be added for Nexus One owners, and, well, it is now available. Current Nexus One owners and those waiting on an order are now able to call in and speak to a live operator by dialing 888-48NEXUS (888-486-3987).
The call center will be in addition to the currently existing email and support forum and will be open for calls between 7am and 10pm PST (10am and 1am EST).
As for the reasons to call the new Google support line, well those are a little limited. It seems that the call center will be handling issues dealing with an existing order (status and shipping issues).
Which means the remaining issues will still fall back to either HTC or T-Mobile. According to the Nexus One Contacting Support page, calls for technical support, repairs or returns will still be handled by HTC. And as you would have most likely guessed, any calls regarding your T-Mobile service will still be handled by T-Mobile.
Basically, it you have an issue with your order you will now have someone to call.
Source:http://androinica.com/