Dealt with noob for my friend, who was selling 180M via Paypal. Worked extremely quickly and MSN add -> completed trade took less than 5 minutes. Recommend anyone who needs a quick sale to use Noob, extremely professional and efficient gold dealer.
Best of luck in the future
I *think* that when you use the xbox for the first time, you have the option to create a new account. This is automatically credited with the membership (atleast this is what happened to me - mine is 3 months old). In that case, you can't sell it.
You need to post proof of ownership, otherwise one of the mods will lock this.
If its a receipt-issued one, block out the code and photograph the receipt & if its an "official" one, photograph the front showing the Xbox logo/3 months etc.