Stargate Atlantis Season 4 will air first in the US on Sci Fi.
The first episode is Adrift. Stargate Atlantis Season 4 international schedule.
Stargate Atlantis crew.

Stargate Atlatnis Season 4 in other countries:

Stargate Atlantis Season 4 will air first in the US on Sci Fi, then Canada and then the UK afterwards, this is only by few days between the US and Canadians and just over a week between the US and UK dates. Its not as bad as last year or previous years where the UK would have to wait for months. 

Stargate Atlantis International schedule: 

US - Sci Fi - Friday 28th September 2007
Canada - Movie Network - Monday 1st October
United Kingdom - Sky One - Tuesday 9th October - 8pm

Stargate Atlantis Season 4 crew: