The bottles need to sit at room temp until they are hard to squeeze, usually 4-6 days. You won't notice much change in pressure in the first 24-36 hours. Once the bottles are hard (yeah, yeah, ha ha), refridgerate them immediately. My LHBS owner said to leave them in the fridge for at least 2 weeks before drinking, but I think you should leave them for at leat 4-5 weeks. My root beer tasted much better as it "aged". When I moved a couple of weekends ago, I still had some root beer that was made in early April and it tasted great.
Edit: I used Cooper's dry yeast, not bread yeast.
"I mean, I've heard that women do fake orgasms, but I've never seen it... It really, deeply upset me." - Aldous Snow, lead singer of Infant Sorrow
-- Kings Full Brewery --
-- Currently Being Remodeled --
Conditioning:Lemstrac Wine, first mead