If you're frustrated with OS X's built in BOMArchiveHelper.app's lack of support for your favorite file types, check out [The Unarchiver][1]. The Unarchiver is a replacement for BOMArchiveHelper.app, much like Allume's [Stuffit Expander][2], but without the proprietary code bloat and annoying upgrade enticements.

The Unarchiver is designed to handle quite few more formats than BOMArchiveHelper. Supported file formats include Zip, Tar-GZip, Tar-BZip2, RAR, 7-zip, LhA, StuffIt and a number of other more obscure formats (see screenshot after the jump). Of particular interest for Mac users is support for RAR files which isn't present in Apple's default option.

The Unarchiver relies on the libxad unarchiving library for the majority of its file types.  Note though, that if you regularly deal with .sitx files you'll still need Allume's Stuffit Expander since The Unarchiver does not support .sitx.

To use The Unarchiver just download it from the site and copy it into your applications folder. Double clicking the app icon will bring up a preference pane that lets you set which archive filetypes to open using The Unarchiver. 

In addition to supporting more formats than Apple's BOMArchiveHelper.app, The Unarchiver is considerably faster. In fact, all the archives I tested it on were unpacked too quickly for me to even grab a screenshot.

The Unarchiver is free (as in beer) and open source.

[found via [Digg][3]]

[1]: http://wakaba.c3.cx/s/apps/unarchiver.html "The Unarchiver"
[2]: http://www.stuffit.com/mac/expander/download.html "Stuffit Expander"
[3]: http://digg.com/apple/The_Unarchiver_Open_Source_alternative_to_StuffIt_Expander_2 "The Unarchiver: Open Source alternative to StuffIt Expander"