Here is the link for the Errata/update for 4th Printing of the PHB
http://www.trolllord.com/downloads/pdfs ... Errata.pdf
For reference, they get the intimidate ability to start with. Opponents save vs. CHA or have -2 against him in a 15 ft radius. They also start with primeval instinct where they can get a 'last ditch' +4 to a STR check. At 4th Level they can do a Whirlwind Attack (attack against 2 people, increases every so many levels). At 6th Level they can get a hit point bump with the ability primeval will.
Not real clear on two things though...
1. whether the every opponent who fails is at a -2 against just the barbarian or any other opponents.
2. Also, not clear if the last ditch is just a skill check or can be used for combat.
I haven't used 4th Edition Barbarian, but would rule no to the first (only barbrian) and would allow a one time bonus for a combat attack.
The thing is there is no "rage" feat penalty for using these which is interesting.