I wasn't able to see Friday's episode until the 11 o'clock airing last night. Good episode. I like the development of the Cylon breeding program, and Roslin "playing the religion card". I'm also kind of liking the Tom Zarek character. There's some developing going on with him, and I think he could be a solid addition to the show.
Mainly, I don't remember enough about the old series to really know "what's coming", so this is all new to me.
As far as who's a Cylon in the fleet, I'm definitely going to say that Tigh's wife is a Cylon. They really left it up in the air when she was tested and passed, but then Number Six mentioned to the Doctor how they'll never know that everyone passes the test.
There's also the copy of Number Six that tried to have Dr Baltar arrested for treason. She's obviously flesh and blood (and circuitry), and still somewhere in the fleet.
As far as sleepers, there is the "Adama is a Cylon" accusation from the Cylone agent that was sent out the airlock by Roslin. I'm not sure that would be such a great idea though.