We don't know a whole lot about Irina, but I already feel for her soooo much. I don't think anyone should give her a hard time about refusing to help the Cullens and the wolves-- if the wolves had killed your partner you'd be pissed to. It's sort of the same situation with Victoria and James-- James apparently didn't have the same affection for Victoria as she had with him, and we don't know if Laurent felt as strongly for Irina as Irina did him.
But as I think about it, I can sooo understand her perspective. Can you imagine what Rosalie would do if she lost Emmett? There would be hell to pay. What if Alice lost Jasper? Esme lost Carlisle? Bella lost Edward? And it's sort of the same thing as when Jacob lost Bella... look at how much pain he was in at the end of Eclipse. It's the same thing with Irina... she's lost the person she loves. So I can totally understand why she doesn't want to help the wolves.
My theory is that Jake will somehow end up meeting the Denali girls in Breaking Dawn. The first chapter of BD says Jacob is in "northern Canada". The Denali girls live in Alaska. So I think that somehow Jacob will run into them, and Tanya's coven will realize he is a werewolf from the pack that killed Laurent. That he is a wolf who took part in killing Laurent. Irina would want to immediately kill him, I'm sure. But since Tanya has a thing for Edward-- or used to, anyways-- I think she'd pull something much more dangerous out of her sleeve. I think she'd take Jake to the wedding and give Edward the ultimatum of either leaving the wedding and going with her, or else they'll kill Jake. That way Irina would have her revenge too-- she'd be causing Edward and Bella pain, since she probably sees Bella as one of the main reasons Laurent is gone. It would be the perfect conflict, because what the hell could Edward do? If he said no and willingly let Jacob die, Bella would FREAK OUT. She may have chosen Edward, but there is no way she could ever stand by and let Jake die. But if Edward went with Tanya, Bella's marriage would be put off which means her transformation would be put off as well... and at that point, I think the Volturi would enter. They know the date where Bella is supposed to be changed, so I think they'll send someone to "check on her". If they saw Bella wasn't changed, there would be hell to pay. So it would be the perfect way to drag both the Volturi (the only as of now unresolved conflict previously introduced in the books) and the Denali girls (the only characters mentioned in the series who have yet to make an actual appearance).
There are holes in my theory, of course... the wedding, for instance. I'm sure there will be people there who aren't werewolves and vampires, so Tanya couldn't exactly go barging in announcing anything because the Volturi would flip if she revealed the vampire secret to a bunch of humans. And even if Edward let, Bella could have someone else transform her... then again I'm not sure she would allow that...
Anyways though. I like my theory. It seems like a good way to drag in all the vampires. And I DO think Jacob is going to end up running across the Denali girls somehow... I don't think it's a mere coincidence that Stephenie stuck him in Northern Canada...
<img src="http://i28.tinypic.com/ipblm8.jpg"><img src="http://i29.tinypic.com/2u8jmld.gif"><img src="http://i38.tinypic.com/9urrlv.jpg"><img src="http://i38.tinypic.com/30lnvye.gif"><img src="http://i33.tinypic.com/1zc1duh.jpg">
[b]Team Jacob[/b]-- Because dogs are better than leeches. Because real men don't sparkle. Because Romeo is a pansy. Because Jake is HUMAN.