HelpGear

CHM, Web Help, and PDF creation is easy with an excellent help authoring tool

handy wysiwyg editor which can be used for editing and translating chm files.
CHM OwnerGuard

drm, security, copy protection and watermarking solution for chm documents
HelpNDoc

help authoring tool producing chm, html, pdf, word, epub, kindle documentation
Aml2CHM

plugin for creaion html help files (chm) from aml pages documents