Abrams told Empire Magazine that there's a reason that he went for the Romulans as the movie's big bad aliens:

The Romulans were … what was interesting to me was that it wasn’t the Klingons. That’s what you expect and it was fun to use the Romulans the way we did. Part of the fact is that they hadn’t seen them for so many years, so that it immediately breaks, for anyone who knows, the rules of Trek to start the movie and have Romulans crossing paths with Starfleet. It jumps in breaking the rules, which I think is kind of fun. That’s not to say it’s not explained and it’s not consistent with canon, given our story... but it felt like we had seen so many iterations of Klingons done that this felt like a way to do something in the familiar vernacular but not so familiar that it felt overdone.

Which isn't to say that we'll be entirely devoid of Klingons in next year's much-anticipated reboot, he went on to explain. It's just that we may have to wait for the DVD to see more of them:

You will see Klingon Warbirds in the movie. Maybe not in the way you expect, but you will see them... There was a big Klingon subplot in this and we actually ended up having to pull it out because it confused the story in a way that I thought was very cool but unnecessary. So we have these beautiful designs that we’re going to have to wait and do elsewhere I guess.

Is that "elsewhere" as in "DVD extras," or "elsewhere" as in "Star Trek II"? Only time - and box office - will tell.

[Associated Press]

According to E! Online:

Collins said his and Bana's Romulan look could have been somewhat inspired by Pirates of the Caribbean. “We’re space pirates,” Collins explained. “Think of Johnny Depp as a Romulan.”

And get ready for some surprise appearances in the movie. "There is, but I better not say," Collins said of possible big-star cameos. "There are certain things that as kids growing up, whether it's Star Trek or other shows at the time, all you got to do is really just hear their voice and your heart warms."

Asked if he was referring to characters and actors from the original television series, Collins simply smiled and said, "Maybe."

I still want to know who that mysterious linguist is who came on set. Could it have been Marc Okrand, we wonder? He's the guy who invented Klingon back in the 1970s, and has spawned a tiny empire of Klingon speakers affiliated with the Klingon Language Institute.

A Romulan Speaks! [E! Online]

According to the site, the new movie will center around a Romulan plot to travel back in time and change history... somehow:

Back in February we reported that a local traffic news helicopter flew over a large rusty object which was being filmed in a parking lot around Dodger Stadium in Los Angeles (we later reported that JFX got some shots of John Cho and a bald actor at that location). Initial speculation was that this object was some kind of ship, and the bald actor was a Klingon. However, TrekMovie.com has learned the object is actually a 'drilling rig' being used by the Romulans and that it is related to an attempt to destroy a planet. The practical location is just part of the larger rig that will mostly be done in CGI by ILM. the bald actor is, of course, a Romulan who Sulu (Cho) fights. Although he wasn't seen by the paparazzi, apparently Kirk (Chris Pine) will also be in that scene, but not part of the fight.

When Eric Bana showed up on the Tonight Show with a shaved head the same week he was to start shooting for Star Trek people took notice. But TrekMovie.com has learned that it isn't just Bana who has gone Kojak. According to sources close to the production, all actors playing Romulans, including Collins and even background performers, were required to shave their heads. TrekMovie.com has been told that the reason the Romulans are bald was at least partly to help distinguish them from the Vulcans. It has also been confirmed that the Romulans in the new Star Trek do NOT have the extra forehead ridges seen in the TNG era (both on film and TV).

Star Trek Villain Spoilers [TrekMovie]