Well, what do we have here? Sure enough, it's that coveted white Nexus S with AT&T-compatible 3G that we mentioned yesterday, and we just got our dirty little paws on it thanks to a friendly tipster. This particular handset was purchased from Negri Electronics, and it's both unlocked and running Android 2.3.3 (Gingerbread), the version that just barely started rolling out to existing Nexus S units in February. A