Here you go:
http://www.fileden.com/files/2010/7/15/2915232/lgl2_10302009.zip"lgl2_10302009.exe" is the main level editor program. "skills.exe" is a program used to edit the skills information for a level. As a freebie, I also threw in my own "PCL2Stat.exe" program which also supports editing the skills information etc, so you can pick whichever one you like best for that purpose. The zip file also contains the LEVELS and STYLES folders, but you don't need to extract those, they should already exist inside Lemmings 2's folder.
Buried somewhere in this "Here I Go Again!" thread are the instructions on how to use the editor. Try and see if you can dig out that information yourself. Enjoy!