I would add it to your resume, as well as mention it in interviews:
College of Educating People (2010 - 2012)
Graduated from X with Degree of X
College of Educating Other People (2012 - 2015)
Graduated from Y with Advanced Degree of Y
University of Online Studies (2015 - Present)
Currently completing my Bachelor of Science Major in Computing as a part time student. Estimated 4 years of part time studies remaining.
This tells employers that you're commited to your carreer, and striving to improve yourself. I'm also in school (part time) at the moment, and in my job interviews I always mention that I'm furthering my education. Once I clarify that my courses won't be taking place during work hours employers are typically OK with it.