Show up to the jail with your ID and see if they arrest you. Seriously.
It would make sense if you could check without subjecting yourself to the risk of your arrest. However, most sheriff departments will not discuss warrants over the phone and the online dockets are not much more help.
At this stage, hiring a lawyer is your best bet. I've found the best solution is to ask the law enforcement officer investigating the case to call me when they get a warrant so I can arrange my client's surrender. Obviously the person under investigation shouldn't do this because of the risk of being interrogated and revealing something to the police.
Hiring a lawyer before you get arrested also allows the lawyer to prepare a solid bond argument, which could be the difference between you fighting your case in jail or at home.