betonline - usually the first online book with lines out and if you're fast you can beat them to some soft openers. first timers can get a 50% bonus
5dimes - another book with early lines and LOTS of options. take the reduced juice option IMO
heritage - decent bonus, some reduced juice options and you get cash back every quarter. they get their lines up early but not as early as BOL or 5D
CRIS - decent bonus on Tuesday. some good lines and good options for bets that other books dont have. no reduced juice
all take credit card though your CC company may initially block the transaction....low limits though...$500 to $999 max in most places. it may take multiple CC deposits to get all the money you want out there
there are more options for NON-US residents (pinnacle and greek, for instance)....