This is not specifically a POL tool but you gotta see it!
Here is a link to an alternative to Worldforge. Worldmaker is a nice tool for editing existing maps. Using this tool you can add or delete statics and terrain (maptiles) in a realtime, 3D "In-Game" view of the map. It also allows easy placement of multis which then are mapped in as statics for quick placement of houses and structures. One caveat though; when placing multis using this tool, you have to remember to remove doors as they will become static (unopenable) if you don't.
It runs as a standalone tool and is not emulator dependant.
There are other tools there as well but I was unable to get them to run for some reason.
Worldmaker is an excellent tool for what it is created to do. It is in its infancy so expect it to get better as Punt, the developer, continues working on it.
Check it out folks.
Oh yeah!
I almost forgot the link.
*smiles*
Here it is:
http://worldmaker.ryandor.com/news.php