70 locks are quite squishy and can be quite hard to play. However, if you get the hang of it, then affliction would probably be the specc to pick.
Set off with haunt > UA > corr > immolate > Agony and then spam fillers - I haven't played a lock since ToC really, so I haven't followed the changes.
It seems to me that there are some demo locks out there aswell, I wouldn't know how that works though.
The gear would be the same as mages, brutals with whatever proper sunwell / BT Gear you can get your hands on
Enjoy the bracket mate