A new preview of Half-Blood Prince was released, though is difficult to listen to as a result of the recording. There are new sequences shown, however, between Harry, Ron, Hermione and McGonagall, Dumbledore in Slughorn's home, and much more. It can be seen below:

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McGonagall: Why is it always you three? Hm? When something happens?
Ron: Believe me, Professor, I’ve been asking myself the same question for six years.

Also, there will be a Half-Blood Prince preview shown tonight on NBC during the season premiere of Merlin, starting at 8p.m EST. We will have that segment up as soon as it is made available online.

Source: Portus

UPDATE: The Half-Blood Prince segment aired during NBC's Merlin showed the Tom Riddle memory from the orphanage, the same video released on a Canadian network days ago. No new footage was released.