It looks to me like FireFox itself doesn't support touch events prior to version 4: https://developer.mozilla.org/en/DOM/Touch_events
No touch events = no pinch to zoom. Chad Killingsworth -- You received this message because you are subscribed to the Google Groups "Google Maps JavaScript API v3" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/google-maps-js-api-v3?hl=en.
