The following are tools commonly used in editing levels in Abe's Oddysey and Abe's Exodus.
Tutorials for using the tools will be released at a later point, or feel free to write your own.
Abes Oddysee and Exoddus PC level editor
Tool released by Paul used for editing levels of the aforementioned games.
See his home page http://www.paulsapps.com/Downloads.aspx.
A set of tools including an old version of the level editor, use the latest editor on his site for actually editing the levels. Included are: Paul's Level Editor 0.5 (old version, do not use) CamTool (not needed at the moment)
LVL Extractor (extracts the files packed in a level file, commonly used for extracting images/animations and rebuilding levels to include game resources for slogs/paramites/scrabs) LVL Builder (used to combine lots of files into a single level file) readme files!
Download his tool set here http://filesmelt.com/dl/Pauls_LVL_Tools_ALL_EDITION.zip
Gimp (image editing)
A free tool used for editing images, use it to help create rough designs of your level as well as create bmp files to import into a level as a background image known as a cam.
Check out their home page http://www.gimp.org/
Adobe Photoshop (image editing)
An expensive but fancy graphics tool which can be used to create images to be used as cams/backgrounds in your levels.
File Resources For Editing