JPGRAR is a simple tool for simplifying the RAR-in-JPG trick.
It's basicly a GUI frontend on "copy /b/ image.jpg+hidden.rar out.jpg" or "cat image.jpg hidden.rar > out.jpg".

The interface is just about non-existent. It merely opens three file dialogs in a row for you to choose the filenames.

Download:
Current: JPGRAR_0.2.zip (31k)
Old: JPGRAR_0.1.zip (31k)
Win32 binary. Source is included (GPL).

Changelog