http://en.wikipedia.org/wiki/MP3 and "AAC":http://en.wikipedia.org/wiki/Advanced_Audio_Coding--are both proprietary codecs which means that any application that wants to use them have to pay the owners of the license. "Ogg Vorbis (.ogg)":http://en.wikipedia.org/wiki/Ogg_Vorbis is a non-proprietary, open source codec developed by the "Xiph.org foundation":http://en.wikipedia.org/wiki/Xiph.Org_Foundation. There are a number of advantages to the .ogg format, most notably a variable bit rate which means that you can fit more complexity into the same size file. It used to be that iTunes users couldn't play .ogg vorbis files, but that's no longer true. There's a "Quicktime plugin":http://sourceforge.net/project/showfiles.php?group_id=41359 to allow for playback and "Ogg Drop":http://www.nouturn.com/oggdrop/index.php for encoding audio CDs. Unlike most encoders, Ogg Drop also accesses "CDDB":http://en.wikipedia.org/wiki/CDDB so song data is automatically retrieved from the internet, saving you the pain in the ass of typing it all in yourself. Previously featured _Killer Apps for Mac._ * "Adium":http://duenos.net/article/129/killer-apps-for-mac-adium - an alternative chat client * "App Zapper":http://duenos.net/article/231/ - tracks down all the caches and libraries for deleted applications and deletes them * "Darwiin Remote":http://duenos.net/article/193/KillerAppsforMacDarwiinRemote - an application that allows the use of the Wii-remote as an input * "Disk Inventory X":http://duenos.net/article/163/KillerAppsforMacDiskInventoryX - visualizes the hard disk * "img2icns":http://duenos.net/article/274/KillerAppsforMacimg2icns - A conversion tool for making any image into a .icns icon file * "iStumbler":http://duenos.net/article/312/KillerAppsforMaciStumbler - A far more detailed wireless network information tool. * "Mac Pilot":http://duenos.net/article/174/KillerAppsforMacMacPilot - an interface to control more options on the Mac * "Sidenote":http://duenos.net/article/111/killer-apps-for-mac-sidenote - a VERY helpful note-taking program * "SizzlingKeys":http://duenos.net/article/119/killer-apps-for-mac-sizzlingkeys - allows universal control of iTunes through simple hotkeys * "Tangerine":http://duenos.net/article/150/KillerAppsforMacTangerine - analyzes and organizes the iTunes library by beat characteristics * "TV Shows":http://duenos.net/article/232/ - automatically downloads torrent files of TV shows * "UnRarX":http://duenos.net/article/234/KillerAppsforMacUnRarX - very good at decompressing .rar files * "Vienna Reader":http://duenos.net/article/204/KillerAppsforMacViennaReader - an OS X-integrated RSS reader with an internal browser * "VLC Player":http://duenos.net/article/228/ - the best media player in existence, it plays anything