"Need a virtual office? You can try phpGroupware, which is an
official GNU Project. If you're not sure how to install it, just
follow along with Don Parris as he installs the latest phpGroupware
on a hosted Debian GNU/Linux System.
"I am installing phpGroupware on a hosted service, using PHP4
and MySQL 5.x (they recently upgraded, but haven't yet changed the
version number in my info page)..."