okay then why does the iphone 3G S not have background processes? it could have been another selling point for the 3G S over the 3G
Because one of the strengths of Apple is that things are simple.
"Can I run programs in the background?"
"No"
That's simple. It's not...
"Yes, but only if you have a 3GS and it's plugged in."
Is that a good choice on their part? Well, not if you're a nerd, but for 90% of Apple's customers, being simple is WHY they buy Apple products. So that's why they do stuff like that. It's what most of their users want.
So what does this mean? I suspect they'll enable background processes on the 3rd gen phone and the 4th gen phone WHEN the 4th gen phone comes out. Then, you get this:
"Can I run programs in the background?"
"Yes, if you have one of the last 2 models."
So there's an "if" in there, but it's a much smaller, less important "if."
That's how Apple works. Wait for the "if" to become small and unimportant. Then they'll make their move.
EDIT: This is the same reason they killed the iPod Mini when the iPod Nano came out. The Mini still sold well, but it added confusion over which one to buy, so it had to go. Same principle here.