"CHM Encoder may decompile your CHM file (Compiled Windows HTML Help) or e-book and extract all source files. This tool free for use and work easily and quickly.

Want you convert CHM to HTML and view that in your PocketPC or in your web pages? Try CHM Encoder now!

The program supports command line. Using batch mode, you can convert several documents simultaneously:
chmencoder.exe [chm_file] [destination_path]"

Looks like a nice lightweight solution at just 329Kb