See Getting Started With Development.
What is WebOS Ports?
WebOS Ports is an open source firmware distribution for smartphones and tablet computers based on the Open webOS mobile operating system.
Basically, it is the (Open) webOS "Community Edition" project. You will see some old references to WOCE for that reason.
Read about the supported devices here.
What is Open webOS?
When HP pulled the plug on what was left of Palm, it produced an open source version of the webOS that ran on the HP Touchpad. That is Open webOS. LG, who bought the Palm division off HP, sponsor it now.
We have some cool material on it here.
What is LuneOS?
LuneOS is the name of WebOS Ports' Open webOS. Lune refers to the user interface in legacy webOS, LunaSysMgr.
What is LunaCE?
Luna Community Edition. It is a Touchpad thing.
rwhitby August 2012:
LunaCE (formerly UberLunah) is a collection of all the best LunaSysMgr improvements for the HP TouchPad, rolled into a single installation package.