Oh, I just made a very similar sound as the screaming synth. I used Massive, it was very easy Anyways, get the Emulated version of th OSCar, since I think that he actually used that on the Alpha Centauri track, very easy to make a really screaming sound with that one (We had it in the studio back in Sweden). Oh, and here is a link to the WIKI about Posefort. http://en.wikipedia.org/wiki/Hallucinogen_%28musician%29
I like the last line a LOT: Simon Posford is heavilly influenced by Ozric Tentacles and Eat Static