Didnt see any other thread about this on here so I'd thought I'd post this.

If you need to get your dark/light side up quick, Diplomacy is an amazingly easy way to do this. You send your companions away on either dark or light side missions, and you get rep with that side when they return. I would suggest people to not use it before level 50 though, unless you are not looking to get your mount asap.

I leveled my dark from 6900 to 8800 in 5-6 hours yesterday evening, starting Diplomacy from scratch and getting it up to about 250.