Corvette is correct on that one.  In a general given basis sites that are sent off to Visa for approval can come back as quickly as 3-5 days.  However, this does not guarantee that every account sent to Visa will be processed in the same amount of time.  The actual time frame itself account approval from Visa is 7 -21 business days.
Hope that helps clear up some confusion.  
Regards,
James A
Client Support Supervisor
1-800-510-2859
CCBill.com