I posted this in the creddie thread, but I'll post it again here, because more than 3 people might read it
I'm going to spoiler tag part of it which includes my reasoning.
I'm 100% certain that creddie kiss is going to turn out like one of JD's little fantasy sequences on scrubs and be a complete blatant ship tease.
I don't think it's going to be "real". It could be a fantasy, a vision, a dream/nightmare, virtual reality, hallucinations or a final moments death sequence, alternate/mirror/bizarro universes but that's very sci-fi. It will be unlikely to be anything but the fantasy or dream. Everything else is too "mature" for this show.
Dream Sequence. Maybe. They could make the whole first part of the episode a dream, end it just as he's about to kiss carly, then show the "real world" and it goes through until she kisses the other guy. Or they have the night before the party, the dream part would be in the middle somewhere, Freddie has a dream about the party, Carly's date is a jerk or whatever, Freddie rescues her, Ms Benson comes in saying to get ready for school, and they show the actual date/dance at the end of the episode.
The writers have already used it once on iDream of Dancing, where they did an almost identical "Freddie rescues Carly" dreamplot. Except he didn't kiss her at the end.
Fantasy Sequence. Refined/Pioneered/brought back by Scrubs (something similar would be the "remember that time etc" jokes on Family Guy), it could be all in his head. Kisses or Near-Kisses = Ratings gold (apparently), and make good trailers.
So they stick in one of these after they come back from the 2nd last or final ad-break, Carly rejecting her date or Freddie rescuing her from an **** she goes over to Freddie then just as they are about to kiss, Sam donks him on the head with a fat-cake or Gibby interrupts them, and he's left back in reality watching the real "guy of the week" kissing her. These can be done very quickly, a single minute is usually heaps and heaps of time to pull one of these off, and it doesn't interrupt the rest of the episode.
The most important thing as it relates to seddie or creddie, is if there is any type of reaction from Freddie about what happened. The writing could make it an explicit nod towards future Seddie by making Freddie decide he's "done" with Carly, or that he's not going to get her, or whatever, so long as he decides that Carly really doesn't like him, and he gives up.
The flip-side is that he is still hurt by seeing her with other guys, and he decides not to give up at all, strengthing his carly resolve. It will probably be one of the most shippy parts of any episode in "season 3" (and by shippy I mean actual obvious shippiness, not "sam beats him up = seddie true love).
This spoiler part contains information gathered from danwarp and twitter that some people may not have read/seen, and may not want to, so I'm spoilering it. It's kinda "evidence" for my non-spoiler thoughts:
***SPOILER***
There is an near-identical picture to the creddie kiss picture (which some people use as an avatar here), but it's with some random guy who will be probably be Carly's love interest of the week. So I'm assuming there is a near-identical piece of film in the episode. Otherwise why take the picture of the 2 identical scenes?
Dan has said to all the crazy seddie shippers not to take it at face value.
Well that implies to me it's not part of the true reality of the show's characters (such as how the dream dancing in iDream of Dance isn't real). It happened on the show but not in the reality of the show.
If it's not a dream or whatever, and it's legit, real, then it's again with the reactions. They could kiss, Freddie could decide he doesn't feel anything after all, and it kills Creddie off for good, leaving the door open for Seddie. Carly could decide that well just maybe she does feel something, and it keeps creddie going.