Certification in Instructional Designing

I would suggest you look at James Madison University. I am in the middle of a master's degree program in Ed Tech but I started out getting a certificate in E-Learning and decided to go for a second master's degree. It's all online but the access to professors and support from professors is amazing. There are a number of options as well - it just depends on what you want to do.
My advanced video production class is currently working on two videos for JMU on the ed tech program. 
I have a master's degree in Applied Behavior Analysis from George Mason University - they also have an instructional design program that I am accepted in but I decided to go JMU. Aside from the stellar professors and really well-designed courses, it is the most economical I've seen.  I will be 75% complete by next summer when I plan on an international internship in the UK (virtual internship as part of the program). 

If you have questions, feel free to email me. Nancy (hemenwnp@dukes, jmu.edu 
And take a look at their E-Learning certificate.