You can certainly find a lot of age-restricted retirement communities with great amenities; however, what kind of public transportation are you looking for? With most of these communities being on the outer edges of our Valley, the light rail certainly doesn't run there and often times, buses neither.
Feel free to visit my website http://www.MetroPhoenixAgent.com
where you can search for retirement communities under the 'Search MLS' tab and then 'Subdivisions' and then 'Age Restricted'.
If you don't want age-restricted, then the public transportation becomes much easier and finding the right area will largely depend upon your price point.
If I can be of further assistance, please do not hesitate.