What keys are present in this song?

Very interesting chord sequence! I haven't heard the song so I don't know the flavour of it. However if I was to look at it from a chord structure point of view I would say;

D C G - The key of G major

Bb F Fm Gsus4 G Bb Bbm Ebmaj7 Cm G Gsus4 G - The Key of Bb major

Fm Ab Eb Fm Ab Eb Cm/G G7 Ab Adim7 Ebmaj7 Dmaj7 Dbmaj7 Db7 Dbmaj7 Gsus4 G - The key of F minor or Eb Major or C minor?????

Remember, that is only my view on it, looking at the chords and seeing what keys they 'fit' into.

Basically with sequences like this it could be viewed in many ways and none of them wrong just different opinions.

This is an interesting song. I would say that it stays in the key of G the whole time, and everything else is related through backward, kind of messy, cycle progressions. Think "Hey Joe". There isn't a solid V-I anywhere that leads to a different key. Just listen to it and tell me you don't get a falling feeling through most of the song.

Now if you were to, I don't know, want to take a solo on the changes, then looking for the key centers to play scales around is going to be tricky. I would take it chord by chord; again tricky but we don't play guitar because it's easy. Right?

Yes, as Steve said a tricky one this. However I tend to agree with the keys he has said. The song of course could be said to be in one key only and all the 'other' chords be classed as accidentials!! It is important to note that when determining a 'key' that the stongest chord or note i.e. the one you seem to want to resolve to is usually the key signature. Music is all about sound and harmonics and relationships between chords and notes so any other suggestions??????