When is Python 3 going to be used regularly?
 

How long will it be or probably be before everyone's using Python 3 for everything?

I think it may be awhile before all the major projects are using python3 as it is not backwards compatible. Some projects are doing a gradual changeover where they first require the latest 2.x version and will later require 3.

Personally I'm hoping things will move a bit faster.

once Blender 2.5 alpha 2 is blender official 2.5

once the first updates to the new blender is out and things are ported to it .
until then ...