One of the most common questions asked is “When will imagery of a particular area be updated?”

Google recently introduced a beta version of 'Follow Your World', which is a new tool that notifies you when imagery is updated in Google Earth and Google Maps: http://followyourworld.appspot.com/.

You can also read about the announcement on Google's Lat/long blog:
http://google-latlong.blogspot.com/2011/01/sign-up-for-imagery-update-alert.html

For list of recent imagery updates check out the previous announcements found at http://www.gearthblog.com/