It's called UnrealEd

Publically, no. Only the 2.5 one was leaked/stolen. In my research, it is/was possible to do it for 2.3 but it involved some hacking. Something along the lines of exporting the resources to the free/student version of UnrealEd then building a map, compiling and then hex editing the map to work with the "paid" engine. There was also something about a bytecode converter which I looked into at one point but never found one for 2.3. There seems to be 2.5 and 2.6 versions though. I contacted iZi (original starter of this mayhem and aa-maps.net) about mapping on 2.3. He actually took the time to convert a texture to the free version of UnrealEd for me when I was first interested in all of this.
iZi's work:
http://dl.dropbox.com/u/464376/mAApPackFiles/facade.7zI did have a decent amount of fun with a hex editor and the maps. You can change staticmeshes or just delete things altogether. Here's some simple stuff I did a while back:
http://dl.dropbox.com/u/464376/mAApPackFiles/2.3%20mod%20maps.7zAlso, I don't know what Crusade would think of this but I know he released a BUNCH of his work and sources on various forums and a lot of this stuff is super old... here's a huge collection of mods for 2.3 that I've collected over the years if you want them:
http://dl.dropbox.com/u/464376/mAApPackFiles/2.3%20Server%20Mods.7zI also have hacks:
http://dl.dropbox.com/u/464376/mAApPackFiles/2.3%20Hacks.7zQuote from a forum about making maps with the free version of UnrealEd:
Basically, you can make a mesh in 3d studio max, export it as ASE,
and import into UnrealEd, or open an existing meshes package in UTPT,
extract the mesh as 3ds, load in 3d studio max and export as ASE, then import to UnrealEd.
Assuming 2.6 or earlier...
With unrealed make a little map, make an interaction, make some actor in their
thats capable of loading up your inbedded interaction. Build and save the map,
run it throught the necessary bytecode converter. Open up with hex editor,
change the sixth, i think, byte from 01 to 00. This changes the licensee mode
stuff, so AA will actually load it. Save as a .aao then drag it onto your AA icon.
AA should load, drop you in that map, and load your interaction up for ya.
Quite ingenious in its simplicity.
If there's something specific you need or can't find, let me know. I literally have 7.29GB of AA stuff... and that's compressed with 7Zip. Enjoy

On a personal note.. AA 2.3 was and is still the best.