Not the official (Sorry!) but has been tested on multiple Curves (AT&T 8310 (OS 4.5.0.46) & Sprint 8330 (OS 4.5.0.33) & AT&T 8800 (OS 4.2)) and works fine. Unfortunately no love for my Sprint Curve running the stock 4.3. Read more about it here:
Google Maps 2.2.1 Voice Control On Your Curve & 8800!!! | BerryReview
Download here:
http://www.google.com/gmm/apps/v2.2....=en&noss=1