Just rang my local O2 store to ask about Friday;
Q) Have you you got any iphones?
A: Not yet, we're expecting them to be delivered tomorrow.
Q) Any 16GB phones?
A: No. We're only getting 8GB ones for Friday, i don't know when we're getting the 16GB model.
Q) What time are you open?
A: 8.02pm
Q) I'm an existing iPhone customer, can you upgrade me to iphone 3g?
A: We should be able to upgrade you in-store on friday without any problems.
Good and bad news there as i was hoping to get a 16GB model!!
I do live in a fairly small city in the UK (a large town really), so perhaps it's only the big O2 stores in the big cities that will have the 16GB models...
So if everyone that wants a 16 gb version holds out for a "few weeks" as O2 puts it, its going to be an embarrassing "launch day" or O2 with lots of 8gb versions sitting in the stores!