You can use the ezW2 Software backup and restore functions to transfer the W2 and 1099 data easily if you are HR manager or buisness owner
http://www.halfpricesoft.com/business-blog/post/2012/11/07/How-to-roll-forward-W-2-and-1099-data.aspx
However, if you are a CPA and have many accounts, it will be easier to transfer the data manually. Here are the steps on how to copy the data from ezW2 2011 folder to ezW2 2012 folder.
The database file is .mdb file (Microsoft Access Database file)
Step 1: Open ezW2 2011 folder
ezW2 2011 default folder
C:/Program Files/Halfpricesoft/ezW2(2011)
If you are using Windows 8, 7 or Vista with default settings, the default ezW2 2011 folder can be:
C:/Users/**YourName**/AppData/Local/VirtualStore/Program Files/Halfpricesoft/ezW2(2011)
Step 2: Copy the .mdb files to EzW2 2012 folder
C:\Users\Public\Documents\Halfpricesoft\ezW2(2012)
Step 3: Switch current account
Start ezW2 2012, select this new database file as your current database file by clicking the top menu "Company Management->Select Company".