I am interested in forming a Holdings Company (Doe Web Holdings, LLC).
 I have a couple of websites that I would like to start under the
Holdings Company.  My 2-part question is, how would I go about forming
this company legally as an LLC (is it just like a normal LLC), and how
would I add companies under this Holding company (does each new
company have to be incorporated individually, or can I get by with a
DBA?).

The things that should be considered are minimization of tax, and
lowest cost.  I am currently a small business just about to get
started.