Since a lot of people have been asking this lately, I am going to condense the information from other tutorials on this site as well as information I have learned though trial and error with COD4.
Where to Begin:
Following one of the following methods:
(Note: Wireless bridging has proved very difficult for some and easy for others due to many factors. I recommend using ICS bridging if at all possible)
1) Krafty's Tutorial: Wireless Bridging
http://www.se7ensins.com/forums/brid...nd-prompt.html
2) Krafty's Tutorial: Router Bridging
http://www.se7ensins.com/forums/brid...alarm-pro.html
(It say's old but I use this method for both Halo 3 and COD4)
Now how to standby:
Once you have your bridge complete you will need an auotstandby controller of some sort. For COD4, I didn't have much luck with ZAAS from this site, but I have yet to have a problem with:
Macro Recorder / Mouse and Key Recorder. . This is a macro key recorder program that you can create your own key recorder and change the delays etc. You can play around with it or you can download my setup here:
RapidShare: 1-Click Webhosting Password for macro is: Se7enSins.com
Putting it all together:
1)Bridge your connection first through C&A.
If you haven't already done so add this range 65.59.234.1 - 65.59.234.255 into your TRUSTED list and label it XBOX Live. Also add IW's ip address 69.60.4.143 into your TRUSTED list and label it COD4. (You should see both of these appear in C&A).
2)Turn on your XBox and log into xbox live. Before preceeding into the game, turn your firewall to high and then start searching for a game. No game should be found and you will be given host. Turn your Internet Zone firewall to medium and let people join.
(When playing with people in your party, you will obviously also need to add their IP's to your trusted list before beginning your search)
Make sure there are enough people in the game before you use the macro KR.
Run the macro and now you are standbying. You and your friends should be able to run around without any problems with the rest of the players lag and appear to be standing in place.
ADDITIONAL INFORMATION:
1)If you decide to remove a player or two for what ever reasons it will result in a bad hosting record and host will no longer be given to you. Once this happens and you stop getting host simply go back to dash and clear your cache, this seems to remedy the problem.
2)You can clear your cache by going to the last blade, highlight memory, press A Y X X Right Bumper Left Bumper X X, it will then ask you if you would like to perform maintenance on the drive, select yes and your cache is now clean and that bad host record is gone.
3)This works as well if for any reason you get "host ended game" which will cause you to not be able to host until you clear your cache.
4)Play around with the settings of your macro. Not one particular setting will work for everyone. The most important thing to do is make sure the settings are high enough to cause a disturbance with the Network, but not too much that it ends the game.
5)For different game types, you should run the standby during different times of the game. Doing so during an Airstrike is not that beneficial nor is it when there is a helicopter present. If you are playing S&D, stop it between rounds so it doesn't end the game.
COD4 Bridging & Standby Tutorial
. I only supplied this information for people who want to know how to do it so they can if they chose. I also boost once in a while with my brother, but isn't this in essence the same thing? Manipulating the network to play a game that is setup to let you gain experience/rank without getting it the legitimate way? I'm not saying it is, but who knows if people get caught doing this like in Halo 3 they might just get a ban or be deranked. 
Linear Mode
