Many people think its impossible at the moment, but i have a method that works and requires only another xbox, and another computer. This is what you need:- Teamviewer ( A remote support ) software which requires admin rights!
This is What your friend will need: DOWNLOAD HERE!!! - Teamviewer ( A remote support ) software which requires admin rights!
- Zone alarm Pro
- Cain and abel
The basic concept of how this works;
So you know people bridge another person host, using their computer and their xbox, well what if you had access to their computer why they were away or sleeping, you control cain and Za. In other words "BRIDGE YOURSELF HOST".
Before you start make sure cain is installed and zone alarm pro, and make sure everything is set up:
HOW TO SET UP ROUTER!!! THIS IS WHAT YOU DO ON YOUR PC!
1. Download team viewer from the official website on the link above. 2. Either install or run the software (install is better and saves time just incase you pc crashes) 3. open team viewer its a blue icon on the desktop 4. it will show you a ID and a PASSWORD 5. Ignore this 6. This is where you friend comes into it THIS IS WHAT YOUR FRIEND DOES ON HIS/HER PC:
1. Download team viewer from the official website on the link above. 2. Either install or run the software (install is better and saves time just incase you pc crashes) 3. open team viewer its a blue icon on the desktop 4. it will show them a ID and a PASSWORD 5. now your friend has to give you the id and password (make sure that both team viewers are open and say at the bottom "SECURE CONNECTION) RIGHT NOW THIS IS WHERE YOUR PART COMES INTO IT, AND WHERE YOU BRIDGE YOURSELF! 1. you should now have this on screen: (if not you have installed wrong) 
2. now enter your friends id and hit "CONNECT TO PARTNER"
3. After about 5 secs it will require a password
4. enter the password your friend gave you
5. a screen will pop up on your screen "THIS IS YOUR FRIENDS COMPUTER" and you have control!
6. now get your friend to open cain and abel aswell as Zone Alarm pro!
7. thats it, you can input your ip, control cain, and ZA
8. you can now bridge
yourself host! using a friends computer and there xbox.
I USE THIS METHOD AND IT WORKS
IF YOU NEED HELP PM me or contact me on XBL (GT's in SIG)
remember this is not official its just a way i manage to do it
there is no current way of bridging yourself host on your own!
HAPPY GAMING