...but only once a year!
Microsoft has released a new Xbox 360 licensed content transfer tool, that will allow consumers to transfer purchased downloaded content from one console to another.
The tool is designed for gamers to transfer old content they have already paid for to a new Xbox 360 console. It is available through the Xbox 360 website, and requires the use of a PC while the new console is turned on and connected to Xbox Live.
Console owners will have to log in to a Xbox's DRM website with their Live username and password - from there they'll be able to transfer the content to the target console.
Source: Games Industry