The old news on the street is that the Google Maps API v2 will be deprecated in just a few weeks in May 19th 2013. I have a few old Google mash-ups that I never upgraded to v3 of the API that are floating around this site and I will retire those pages when the time comes.
However, one of my v2 mash-ups is a nifty transparency slider that I modified to work with WMS data. I will be updating that site to v3 of the API before the last days of v2. I’ve been saying that I was going to upgrade this app to v3 for a while now and I should probably do that soon. Nothing like the deprecation of a API to get you motivated to write some code!
For more info on the v2 deprecation and a whole bunch of Google Maps news visit the Google Geo Developers Blog.