Here's an open-source utility to help quickly create a proper ePub zip container from a folder.
- Note: This tool is from a MobileRead thread dated 2010.
EPubPack is a very specific tool to build an ePub from a folder containing the ePub structure. It can be used to rebuild an ePub you have unzipped and modified.
To use, select your ePub "mimetype" file and choose a Filename.epub to save as. Then click the "Create ePub File" button. All files inside the source folder will be included in the ePub file.
 Installer with auto-updater:
 Zip download with no installer:
 Source code
License: GPL v3 or later
Requirements: Windows 7, Vista or XP .Net 4.0
 For more information
Please let me know if there are any bugs.