I think Zuko took some notes out of The Prince. Sometimes you need to do evil for the greater good.

Yeah, Azula is definiely NOT going to want to share her power with Zuko, and I'm pretty sure he knew that too when she was telling him about how his honor has been restored at the end. So I think that he's planning something and either everything he did was a part of this plan or that was a lapse of judgment and he's regretting his decisions (leading to a new plan). He may have been changed by his fever (even Katara could tell in the cave; she was willing to heal him), but he obviously did not do a complete turn around yet. Those things take time.

It's a reeeeally good thing Katara didn't waste that special water on Zuko, though, because 1) his scar is awesome and 2) aang probably would have died... and yeah, that would have been bad ^^

i tink he iz up 2 smtin coz of da look , afta aula saiz that Iroh betrayed himself and it aint zuko's fault. idk wat but i certainly tink zuko would make it more interesting if he just be evil for a little more. dats just m3 dou

Zuko's betrayal was NOT an act. Zuko joined Azula because he wanted his honor back and place as the fire lord's son...Get over it people...

its actually plausible though, a stretch...but plausible, did you see the look on his face when he looked at Iroh?(or the other way around) it looked like he knew what he was doing was wrong and he is trying to get close to Azula to maybe attack when shes least expecting it, it makes sense, besides a little positive thinking never hurt anyone it worked for Sokka

Hmmm...I have thought about this. I'm kind of torn between Zuko being on Azulas' side, or Aangs' side.

I really don't know what to think of this episode. But the last actions of Zuko just feel odd. I guess we'll have to see in the next season (which I hope will be here soon).
I have though noticed another oddity about Zuko, which leaves me quite perplexed: his fire-bending style.
I am a professional animator, so I noticed that contrary to the usual fire-bending movements, which are quite direct and angular, Zuko tends to use more fluid movements in his bending. Even great masters of fire-bending like Iroh or Jon-Jon keep to the standard Shotokan-style. But Zuko, especially when he's in a tight spot, falls into air- or water-like moves.
In his first agni-kai against Commander Yao, he resorted to a capoeira-like move to get out of reach and repeats this in Zuko Alone when he fights against the guy with the hammers.
But the most prominent similarity was in this last episode: first, when he decides to stop running from his sister, the move he makes ist almost identical to Katara's when they fought at the north pole. And then later when the two of them whip away at each other, they use almost the same technique, only the element is different.
All this tells me that concearning Zuko there is more than meets the eye. So I'll be waiting with anticipation for the next season.