Scida is an e-book library management app for Mac that helps you organize your e-book collections and manage your Kindle. Books cannot only be copied between your computer and Kindle but Scida also provides usage statistics about your Kindle, and you can edit your Kindle's collections for certain devices (Kindle Keyboard, Kindle 4 and Kindle black).
Features:
You can import your e-books and e-book folders to your Scida library
Collections can be created within Scida library to organize your e-books
Scida auto-detects if your Kindle is connected and you can browse its content
You can import books from your Kindle to your local library
You can send books from your local library to your Kindle
Usage information is available about your Kindle
If you have a Kindle Keyboard, Kindle 4 and Kindle black, you can create, edit and delete your Kindle's collections and add or remove books
Supported devices:
Kindle Keyboard (Kindle 3),
Kindle 4,
Kindle Touch,
Kindle black (2012),
Kindle Paperwhite
(Scida does not support Kindle DX, Kindle Fire tablets, first and second generation Kindles.)
This looks great, I only wish it had a trial available. Does anyone know if it supports conversion like Calibre? Or is it simply for managing your collection?