SuperCheats.com have now published their guide to Metal Gear Solid 4 and Metal Gear Online.
There is a complete walkthrough, details of all the unlockables and some hints and tips.
The guide is accompanied by screenshots from the game and in-game videos.
It's free to look at, and there is a printer friendly option on all the pages.
The guide can be found here:http://www.supercheats.com/guides/metal-gear-solid-4/