OK, I'm just gonna put my idea out there. This could all be in one episode or over a few eps, whichever you guys think would fit it best. So... here goes:
So, after iOMG, Sam and Freddie announce feelings for eachother, but then Carly steps in, and announces feelings for Freddie, and Freddie says he loves both Carly and Sam, maybe like this:
Sam: Me and Freddie, sorta have... feelings... of romance...
Carly: Sam... I'm happy for you, but this is too awkward for me. Not when I... I...
Carly: I don't know how to say this, but I... love Freddie too.
Sam: But... Freddie loves... he loves... me now, don't you?
Freddie: Sam... I do, but Carly is still another girl I love, and I don't know if I can choose...
OK, you probably get the main idea. Both Carly and Sam love Freddie, and Freddie can't choose. This leads to an awkward friendship between Carly and Sam, which in turn leads to an argument, and after a few days of this, Freddie finally speaks to them:
Freddie: Look, you two, I love both of you. Both of you are amazing in your own ways. But I can't date one of you if the other is going to be jealous or upset.
Carly: (after a pause) He's right...
Carly: We can't let him get in between us. We have to wait.
Sam: What do you mean?
Carly: We have to wait for one of us to get over Freddie, so the other can date him freely. It may take a short while, it may that a long time, it may never happen, but we can't date him now.
Freddie: Thanks, Carly...
Sam: OK, I guess I can live with that.
(Carly and Sam hug)
So then, it could go either way, Creddie, Seddie, Neither, but iCarly will be back to normal until whenever Carly or Sam get over Freddie.
So, that's what I'd like to see. The main idea of it, at least.