Markdown for Guitar Chords and Lyrics
Try out Lilypond, which uses a music-specific language, and generates great-looking output.
There is a wonderful software to handle and print nicely songbooks : http://www.patacrep.com/en/index.php The whole setup is not very easy, but the result is quite impressive !
If you need to convert raw text songs to the format needed by this application, I just wrote a small JS script : https://github.com/oliverpool/guitar-tabs_songtex.js (demo link available on the readme)
If you are just looking at getting the the song book printed out as opposed to developing your own application for creating the styled music sheets then you should check out this Transposition App.
If you paste a chord/lyric text file in and then set the old and new keys the same it will give you the desired output.
You can choose to have chord names or the full chord fingering chart (click on the chart to change positions prior to printing).
I'm not involved with this application in any way - I just use it quite regularly when printing out my own music prior to gigging.
Examples of output:
Chord letter only.
Chord finger chart