by installing in my Site may permit users REGISTER, and create automatically an address of
[email protected]?
may install in Shared Hosting Environment PHP/MySQL or needed Dedicated Server?
You can run RoundCube on a shared host. RoundCube doesn't create mail accounts so you'd need to write a plugin or use a different script to create accounts.
You mean is for one mail account only OR is for creating manually many accounts?
I'm not sure what you mean, RoundCube can't create any mail accounts that would need to be done on your mail server.
you mean is email client?
well after install, how setup the email client to get email from an email account, give DOCumentation url?
RoundCube is only a email client, here is the install documentation Howto_Install (http://trac.roundcube.net/wiki/Howto_Install)