How Do I Update Garmin Maps / Voices etc.?

You can update Garmin maps, for units that were purchased with Lifetime map updates, using a computer program called Garmin Express, the program can be downloaded free of charge from Gamin website here :-

After Garmin products are registered with Garmin Express, they can use it to download and install maps onto both the GPS unit and your computer so that they can be used in Basecamp. It is also possible to back-up other files from your Garmin unit to your computer.

Garmin Express can also install updates for :- Operating System Software, Language / Voices, Vehicle icons etc

Garmin Express User Guide (Note :- You can change product)

There is a release date history for City Navigator Maps here :-
http://www.poi-factory.com/node/42417