Subject: Implications of a flat universe?

Recently discovered evidence speaks for a flat universe (The Boomerang 
observations). This stems difficult questions in my mind, all of which I 
can not ask here because of the very strict limitation to the allowed 
length of a question.

What are the implications of a flat universe to the often used balloon 
analogy of the expansion of space? I understand that the purpose of the 
analogy is not to describe the shape of the Universe, but rather to help 
understand the nature of the expansion. Still, a flat universe would seem 
to invalidate this analogy altogether. Doesn't a four dimensionally flat 
universe imply an edge to the universe, something that is trivially 
dismissed in the expanding balloon example? Also, it would seem to me that 
a flat universe would necessarily have an observable center of expansion 
within three dimensional space. Am I right, and can it be reconciled with 
the nature of the expansion we observe? If an edge must exist in a flat 
universe, then is the edge of the universe a borderline after which space 
itself doesn't exist (as the view that not even space existed "before" Big 
Bang would seem to require)?

Thank you for your time and patience.

Re: Implications of a flat universe?