I'm a bit out-of-touch with the whole CCM scene and broad evangelicalism, so all of this appears to be a well-known controversy already. This is what happens when one is part of tradition that does not actively embrace worship bands and Contemporary Christian music. I personally don't have a problem with either, but I do not listen to Christian Contemporary Music.
As I sit and think about all of this, I'm not sure if I have it all worked out. There's nothing blatantly heretical about the song, but that its author is a proactive lesbian gives me pause to stop and consider the relationship between truth and lifestyle. The question is: does truth, even if uttered by a pro-active lesbian trump the actions of the writer? I have my own take on this, but I'm simply going to leave the question hanging at this point.