[Olddudesrule]

I feel your pain! When I installed my LTH's, had to reach around for the driver's side connection behind the head. Once you understand how it's connected, it's fairly easy to get it disconnected, but because of the angle, it's a bitch the first time. Once I got that one, the passenger side was a lot easier. If I remember right, you have to pull a green "t-pin" that otherwise prevents the retaining clip from being pulled open. Once that is done, you push "out" on the blue clip, and the two separate. I apologize if I have the colors mixed up, but you'll understand once you look at it. There is also a few DIY threads on here that show the connection up close, so you can figure it out looking at that.

I have to disagree with Infantryman above, only because I don't think you want to remove the connection from the head, just separate the O2 sensor harness where it connects there. Removing the connection from the head will give you more room to separate the O2 sensor harness, but you will still have to remove the two anyway. Plus if you break the attachment at the block, you'll have to rig up another way to keep the harness up and away.

Good luck!