Possible Duplicate:
Restrict market updates to WiFi network

I'd like to avoid using the expensive 3G data bandwidth for app updates. Is there an app or something that will restrict updates so that they can only happen over wifi? Alternatively, is there a master switch that can disable updates and then re-enable them? The best solution I've found so far is to uncheck the "automatic update" box on each app's Market page. This is tedious at best, and I'm not sure if I would get notified of available updates or if I would need to periodically check every installed app's Market page for available updates.