when i got my iphone, i was pretty clueless about its actual capabilities. I just got one because it was free.
anyways, i had played with a friend of my sisters, anyways, i saw him using his iphone and texting on it, but because of the SMS interface, i thought it was ichat. So anyways, when i got mine and realized there was no ichat on the phone, i called ATT to see what the deal was. I wanted to know HOW i could get it on the phone. She laughed and said I could not download the actual program onto the phone, but i could use some web apps. She then went on to assure me that by "summer" there will definitely be an IM application. So i said "Like July Summer?" and she said maybe, but she said it will definitely be out in the summer.
My guess about the apps that run in the background is that apple is not allowing any outside developers to create a program like that because they want complete control of those types of apps. It makes sense to me, i mean they already have SOME applications that came with the iphone that (in a way) run in the background. I'm no programmer, but isnt the calander always updating and checking for an alert?? I mean, the iphone has LOTS of things happening when you arent doing anything so it's not the iphone CANT have an app like that, but that apple wants to tightly control apps like that.
again, its just my assumption and guess as a novice techie, but it only makes sense to me. It makes more sense than just saying "well, apple will not allow any developers to create apps that run in the background, so there will be no ichat (or IM app) that runs that way.