Installing WP On Different Domains

I have installed my first installation of Word Press which happens to be version 1.5. It was installed in a directory named WordPress–it was a one-click install by my ISP service.

Now I realize that it is within this directory is where my Blog gets installed or at least it was (did I make a mistake installing in WP directory or did
I have a choice of installing in soome other directory (that I would have preferred?).

Also I have several different domains (not sub domains) that I want to install a blog on — and wonder what is the best way of going about this – as some of the domains do not have the one-click WP Install.

Can I simply copy all the files from one domain to another domain and then change certain files like the config asnd then run install from that point.

I welcome your thoughts and advice.
Thanks you,
Charlie Nielson