These instructions must be followed to the letter or they will not work. Do not upgrade to Shelf 2.0 until you have finished with the migration. Shelf 1.1.4 is required.
Important Note:
Any posts with Audio or Image files hosted outside of your WordPress installation will need to be updated manually.
1. Back up you database. This is the MOST IMPORTANT step. Do no skip this or you risk losing all your data.
2. Upgrade WordPress to version 3.1 or higher
3. Install and Activate Shelf Migrate Plugin
4. Verify that you are running Shelf 1.1.4 and WordPress 3.1
5. Navigate to Settings -> Shelf Migrate
6. Click Migrate Shelf
7. Upgrade to Shelf 2.0
8. Run the Regenerate Thumbnails plugin http://wordpress.org/extend/plugins/regenerate-thumbnails/