Makeitone. Freeware which lets you combine a set of MP3 tracks into a single file to make it easy to transport and play. Nice way to make albums out of a collection of tracks.
…we are designing applications to help you pack/join your music files in a single file – whilst still allowing full playability, tag editing and unpacking. You can keep all the songs, from one album, in a single file. Easier to handle, transport and hassle free playing.