Matt,
I am not the best qualified to answer your question, but I have dabbled in this a little, so I'll share what I think is usable in at least some circumstances. I find the biggest difference in the music is the fact that a pianist often plays multiple bass notes, or chords with the left hand, and the guitarist is limited to a bass note with the right thumb. The pianist's right hand and the guitarist's right fingers are pretty equivalent. A simple conversion might be to start with piano sheet music, and transcribe the treble directly. Then add the root bass note from the bass portion of the piano music. From there, you may need to apply some additional theory/creativity to accommodate playability and harmony. For example, your bass note won't work when it's 12 frets from your melody note. To clean up your transcription, adjust the stems to indicate the appropriate digit (thumb or finger), and the correct stroke (up or down). Some songs I did this to are Bela's Lullaby (by Carter Burrell hybrid and alternate picked - the finished version has some fairly complicated picking), Who Wants to live Forever? (by Brian May fingerstyle version), and What Is A Youth? (by Nino Rota both fingerstyle version and flatpick versions. This is not Hector's version - I think his was the Henry Mancini pop music version, and I transcribed mine from the 1968 movie before Hector's lesson was released).
I did a few others that were really simple conversions, but I've seen many that I couldn't even get close to. I think it's more difficult to convert the work of a skilled pianist because of the simultaneous complexity of both hands. It's kinda fun to try though. I will guess that the Coldplay song is a good place to start because their music doesn't seem very complex. Good luck.
wrench
EDIT: Matt, I just looked at this song, and it looks like it will transcribe very well with a lot of latitude for the player. It doesn't have a complicated bass line on piano, so I think you can transcribe a great piece just from a chord chart.
http://tabs.ultimate-guitar.com/c/coldp ... r2_crd.htm. I played along with the video from this chord chart, and it sounded very close. I think you will have good success.
