i'm having the same problem-- no nokia messaging option in the list. i thought it was just because i had the region set to USA, but i tried other regions and no joy.

i had to trick the nokia messaging website by telling it that i had an n95 when i signed up, because it wouldn't let me sign up for an account when i said i had an n900. so i don't know if that has anything to do with it.

this is definitely a major problem for anyone who wants to use this thing like they would their blackberries....