dvdrip is right, Moniker has a militant 5 days for ex, for a transfer out, Name.com may take longer, I think I've seen 6, or 7 days even, Dotster takes long too
GD, Namecheap, otoh let you speed up the transfer out (the losing registrant can), I think even Dynadot allows that...
The WHOIS sometimes reflects the stage the domain transfer is in, but depending on which side you're on, the WHOIS may say the transfer is completed showing the new registrant's name (Sedo has told me that and that they wanna release pymt when I'm the buyer) but when you check the CP then the gaining registrant sees it's still not in his account, so before pymt is completed this needs to be checked
Some smaller/lesser known registrars/resellers may extend the period, when they're on the losing side, as much as they can, you get emails to reconsider, blah, blah, they sound like some gf that was just dumped lol