From Merge MP3:
Merge MP3 files into a single track. Merge MP3 can join files in a wide range of audio formats including 3G2, 3GP, AAC, AC3, AIFF, APE, CUE, FLAC, M4A, MP+, MP1, MP2, MP3, MP4, MPC, MPP, OFR, OFS, OGG, SPX, TTA, WAV, WMA, and WV formats as well as Apple Lossless Audio Codec (ALAC) and MOD Music formats, producing a single playable tune with customizable pauses. Gapless playback option is there to deliver continuous uninterrupted playback. Merge MP3 features a simple and intuitive user interface with drag-and-drop support for easy file joining. You can join a bunch of MP3 files together by using the optional batch mode. In batch mode, you can pre-configure desired settings such as bit rate, file format and silence between the tracks, joining entire folders full of audio files with just a couple of clicks. With Merge MP3, you're not limited to joining just MP3 files. You can merge file in all supported audio formats, producing tracks in any one of the supported formats as well. For example, you can merge a bunch of FLAC files into a single MP3 tune, or vice versa. Not just that; you can merge files in different formats together into a compilation in a format of your choice. If the files you're merging are in different audio formats, Merge MP3 re-encodes them on the fly into a format and codec of your choice. You can use Merge MP3 to reduce the clutter of having hundreds of files in various formats.