Just saw the new Alpha 1 official version is up. A few days ago, I installed the 27007 build “Blender 2.51”. Does anyone know, is that the build now up, or should I reinstall?
Alpha 1 is roughly svn 26970
Check out the updates here:
http://cia.vc/stats/project/Blender
As soon as there’s an update then everyones current version is out of date. 
A few options:
Stick with a build if it works for you. Update periodically.
Build / Download from http://www.graphicall.org/builds/ when there’s an update that relates to what you use blender for.
Build daily / hourly / after every revision.
There are users on graphicall building daily, so no need necessarily to wait for ‘Official’ builds. It just confuses new comers and infrequent visitors to what is a simple thing, build yourself or download daily / weekly / whatever from Graphicall or wait for ‘Official’ builds that are out of date by the time they are available.