T-Mobile only offered the Galaxy Note for a few weeks, until it was cancelled. This obviously created worries that both official updates and the developer community would suffer. However, to ease those worries, the CyanogenMod team has started pushing Jelly Bean nightlies for the device.
Remember, rooting and flashing your device might be dangerous and void your warranty. Proceed at your own risk. None of us are responsible for any possible damages. Read carefully, and follow instructions. Hit the source link for the nightly!