on a standard PC keyboard: option key = alt key, apple key = windows key

coverage of mac os x server services: http://www.anandtech.com/show/4547/mac-os-x-lion-server-review

services are managed from the server admin tool

removing open directory: run slapconfig -destroyldapserver

VNC can be enabled from System Preferences->Sharing->Remote Management. a VNC password will need to be set.

root password can be reset by booting into single mode (holding apple key and S while powering on). then mounting the root volume with /sbin/mount -wu /. finally, run passwd root

resetting a  system account’s password can be done by booting into Recovery (hold Option key while powering on). once in Recovery, open a terminal and run resetpassword.

changing hostname…i tried every way i could think of, but this was the only method that worked: scutil –set HostName <hostname> 

sources:
http://krypted.com/mac-os-x-server/mac-os-x-server-remove-od/
http://famousphil.com/blog/2011/08/resetting-a-password-on-mac-osx-server/
http://www.macworld.com/article/1164599/reset_password_lion.html
http://osxdaily.com/2010/09/06/change-your-mac-hostname-via-terminal/