Well, if it helps you to understand the environment when you are "googling" for help:
You are in a "fairly standard" linux webhosting environment:
Dreamhost webservers are running Debian Linux
Using Apache webserver software(both versions 1.3 and 2.x)
PHP is available in 4.4.4 and 5.1.2 versions running as CGI under suexec
Proftp is the ftp program running on DH
Help is also available on the Dreamhost Wiki where you will find lot's of help available for new users, as well as "advanced" material.
If you have any specific questions, just ask and I'm sure someone here can help.