The Soundtrack for MGS4 is up for preorder on the KONAMISTYLE store. It is to be released on the 28th May and will cost around £15. No other details on what is on the CD or what it looks like are avalible.

http://www.konamistyle.jp/ecitem/item48308.html

A lot of games now are starting to really try with their soundtracks, for example Halo 3 had a great soundtrack and even Super Mario Galaxy's music was amazing. I have always liked the MGS music, but I hope they can step it up another notch to truly compliment the game.

I believe the soundtracks is going to be awesome.
Harry Gregson-Williams has done a great job in MGS2 and 3.
I'm really looking forward for this.
Great post and thanks for the news.

You can now preorder the OST [With a First Press 'Super Jewel Case'] on CDJapan

http://www.cdjapan.co.jp/detailview.html?KEY=GFCA-98