Dual credit in Illinois is clearly growing in popularity.  

Responding to a fifty percent increase in the number of students taking dual credit over the past five years creates interesting challenges for school administrators in Illinois. 

Where Advanced Placement can be taught by high school instructors, dual credit teachers need college faculty credentialing (a Masters Degree in the subject matter or a Masters Degree in any field and 18 credits of graduate level course work in the subject matter).  the determination of what college bound coursework a given high school can offer may well be a matter of teacher credentialing.  This article by Peter Medlin of NPR highlights the opportunities and challenges of offering college bound course work to high school students.