From Mystik Media:
MediaJoin is software that enables you to easily join (combine) all popular audio and video formats into a single merged audio or video file. Formats supported include MP3, WMA, WAV, OGG, AVI, MPEG-1, MPEG-2, and WMV. Optionally include audio tag information for combined output audio files. Settings are available for bitrate, frequency, channels, VBR, and WMA profile for audio files; and AVI audio and video codec, MPEG bitrate, frame rate, size, and WMV profile for video files, providing complete output control.
The software supports more formats than other audio and video joiners on the market. In fact, it is the only complete all-in-one solution for joining (combining) audio and video files. With MediaJoin, you get a MP3 joiner, WMA joiner, WAV joiner, OGG joiner, AVI joiner, MPG joiner, and WMV joiner all in the same application!