works extremely well as soon as u can enter outland instances, more specifically coilfang and higher.

The mobs there will be green to your 70's and therefor still give the pala loads of XP. 4x70 and a lowbie (dunno lowest level to enter there) should net you loads of XP.
Untill that level I always boost with 1x 70 warrior with a bunch of lowbie healers to speed it up and increase XP