Hello folks,  
 
Need some wise words concerning licenses on the Xbox 360 console, you see I'm selling my Xbox 360 Elite very soon but have the issue of being unable to transfer my license from this Elite console to the Halo: Reach Xbox 360 Slim I bought recently. As you'll no doubt know it can only be done once every twelve months and right now I'm unable to transfer all my license content to my new 360. My concern is that my content licenses are registered to the Xbox 360 Elite I wish to sell and I'm not sure if that could affect things. I've had a quick look around and couldn't find a great amount of information concerning removing the console from my account, I don't want whoever buys the system to be able to access my account and it's content through the console if you see what I mean. That's probably not possible but having not sold a 360 before I wasn't sure, I've not at the pleasure of selling a spare 360 before because they all red ringed :D. I wanted to make sure I would be fine selling it, of course there's nothing on the hard drive now so that's not a worry, but you never know.  
 
So do I have any reason to worry or can I just sell the console on without needing to mess around with licenses and such?  
Thank you in advance for any help, it will be much appreciated. 

You can move your gamertag with an USB memory stick. You'll need to also transfer DLC and XBLA game licenses, check out this link: 
http://www.xbox.com/en-us/support/systemuse/xbox360/licensemigration/  
edit: If you don't transfer you'll loose access to your XBLA games and maybe some DLC
 

No reason to worry, unless you also give them the account which you used to buy the licensed content with too.
 
Edit: Just to expand, it's the Xbox that is tied to your account, as oppose to your account being tied to the Xbox. If you see what I mean. 
 
Only stuff you bought with your account will be licensed to that Xbox. So unless the person you're selling it to has your account they won't be able to do anything with your licenses. For now just stay connected to Live to use your content and just switch the license when the timer expires.
 
If you have any other license related questions feel free to PM me.

Thanks for the information, I suspected it was more about the account rather then the console connected to the account but wasn't totally sure. So I can sell it on with that in mind.  
 
Though I have to wonder how it might work for whoever buys the console? Won't they have issues when they try to license the console to their account if it's still connected to mine? 

As has been mentioned 
http://www.xbox.com/en-US/support/systemuse/xbox360/licensemigration/ 
 
 
 A bit on the nature of licenses on the Xbox 360.
Licenses to purchased games and content are tied to the Gamertag that was used to purchase and the offline license that which allows you to play the game without being online or even logged into your Gamertag are tied to the first system the game is downloaded on. So on any other system you have your Gamertag saved too you can download said games and as long as you are logged in you can play them, the original system that the item was downloaded too they can be played while you are offline or even when you aren't even logged in with your gamer tag because the that system contains the originally downloaded license.
 
Preinstalled games like those you will sometimes find on Xbox 360's and memory units have  essentially no license which is why you can play them logged in, offline or online. So via a Usb dongle you should be able to transfer said games between systems and retain their playability, But be mindful of downloading the trial versions of these games on a system that all ready has these full versions or transferring said games to a hard drive with trial versions otherwise the full version of said games will sometimes inherit the trail version license and become unplayable.
*note: when it comes to transferring via usb dongle or hard drive transfer kit make sure to delete the trial versions of games all ready on the new hard drive, or you have a major chance of your full versions of preinstalled games inheriting the trial license, I personally make sure to back up any full versions of games or important items from a new hard drive then format said hard drive via the system settings before I do a hard drive transfer.... at least I do now.*
 
About transferring licenses. 
Make sure to login with your Gamertag and download something on the new system so it appears in your license migration tool area, then you will be able to transfer all licenses your Gamertag has associated with it to the newest 360 you have.   When Transferring Licenses after the license transfer is completed the other systems that appeared in your license transfer will disappear they are effectively forgotten by the Xbox Servers when it comes to associating that system, your Gamertag and said licenses the database for licenses on that system and on Xbox servers for that system is deleted and started new.
 
Selling your system and licenses.
If you do not transfer licenses and as long as the games are deleted from the hard drive the new owner of your system will not have access to them unless they have your Gamertag because licenses are all so associated with your Gamertag, If they downloaded the games from their Gamertag these versions would be considered Trials and while the offline license for the full game would still reside in the Xbox 360's database they would only be able to access the trial version since that is what they have associated with their Gamertag Even full versions of said games would be a license associated with their Gamertag.  Even after selling your system the Xbox servers still associate that Xbox ID and serial with said licenses and Gamertag and you can do a license transfer at anytime, Xbox servers will delete their database and remove the entries in the license associating your gamertag and games in the database of said Xbox 360 when it next gets online.