Do you mean Windows Vista?
MSDN and TechNet subscribers have access as well as many of the Technical
Beta members.
There are also partner programs within Microsoft that have access.
And other Microsoft programs.
The preview is reported to be freely available in January as well as retail
sales.
More information is available in the Vista newsgroups.
As for torrent etc...
Many also get their pirated software from such sites.
Since the source is illegitimate, there is no assurance the software has not
been tampered.