Update 11 Oct 2012: Checkout the self installer tool [ here ]
GEOID 2012A has been out for a month now.
I complied Ashtech Geoid .GEO files and have made them available for download.
http://www.alltopo.com/out/ashtech/G2012A/Geoid12A.zip
Decompress the ZIP file and then place the Geoid12A.geo file at this location (in Win7 64):
C:\Program Files (x86)\Common Files\Ashtech\Geoids
‘GNSS Solutions’ and the ‘Geoids’ extract tool will find the file the next time they are started.
If you are looking for GEOID12A for Carlson SurvCE, check out:
http://update.carlsonsw.com/kbase_main.php?action=display_topic&topic_id=843