After adding my first lot of 12 best free apps for Mac OS X, I have decided to compile another 12 great useful apps for Mac that are completely free!

Adium
Adium is a free and open source multi-protocol instant messaging client for your Mac. Adium allows you to integrate all your instant messaging accounts into one. Adium supports: MSN, Yahoo, Facebook, Jabber, Twitter, ICQ & much much more.



Boxee
Boxee is a free Home Theatre PC application. Boxee has a nice looking and easy to use UI, supports various audio & video file formats, integration to on-demand internet video streaming, 1080p HD support and much more.



The Unarchiver
The Unarchiver is a simple, free and open source data decompression utility that is more featured than the standard Archive Utility in Mac OS X. The Unarchiver supports multiple file formats such as: Zip, Tar-GZip, Tar-BZip2, RAR, 7-zip, LhA, StuffIt and much more.





Wyse Pocketcloud
Wyse Pocketcloud allows you to control your PC or Mac from your iPad, iPhone, iPod Touch, and Android device. PocketCloud gives you secure and easy access to your computer anytime and anywhere.



Thunderbird
Mozilla Thunderbird is a free and open source email and newsgroup and news feed client. Some features include: message management, junk & spam filtering, tabbed user interface, themes & extensions, and much more.



NeoOffice
NeoOffice is a free office suite that is made exclusively for Mac OS X. Unlike OpenOffice.org & LibreOffice, NeoOffice takes advantage of Mac OS X Lion's features like: Full-Screen more, Versions & Resume.





xPad
xPad is a simple yet useful notepad application for Mac OS X. xPad comes as a replacement for TextEdit and Stickies in Mac OS X.



Folx
Folx is a free internet download manager for your Mac. The free version of Folx offers: downloading in multiple threads, built in torrent client, managing the speed of your downloads, settting priorities for downloads, easy integration with your web browser & more.


FileZilla
FileZilla is a free and open source FTP client program. The user interface is well layer out and easy to use. Some of Filezilla's features include: IPv6 support, drag & drop, tabbed UI, directory comparison, configurable transfer speed limits & much more.



iSquint
This program gives you a quick and easy way to convert your videos for your iPod or PSP. The interface is simple and painless, just simply drag and drop. iSquint also lets you adjust the quality of your video and has H.264 encoding.



Facebox Pro for Facebook
A very useful program for Facebook lovers. Facebox Pro is a small program that puts an icon on the right side of the menu bar. When clicking on it, a drop down box appears with your Facebook account. Now you can stay logged in to Facebook without having to use your web browser.


Caffeine
Caffeine is a simple but very useful program. With the click of a button, you can prevent your Mac from automatically going to sleep, dimming the display or starting the screen saver. Caffeine is discretely located in the right hand side of the menu bar.