MultitrackStudio lets you record your own songs. You can record instrumental or vocal tracks while playing along with previously recorded tracks. You can mix the tracks, add audio effects, edit mistakes and finally mix the song to a single file that you can use to make an audio CD.
In addition you can use a MIDI keyboard to play instruments you don't own or can't play.
MultitrackStudio is straightforward to use. The free Lite edition is limited to three tracks.