Internship paid vs unpaid on CV I have interned in two companies while I was conducting my undergraduate studies, one of the internships was unpaid and the other covered transportation expenses.

My question should I mention in my CV that these internships were unpaid or voluntary?
And does this issue make a difference in the eyes of the graduate admissions committee? 

The nature of the internships is related to my undergraduate studies (general computer skills), but not very related to my research topic I want to peruse.
Whether you were paid or unpaid is a matter of compensation, which is not something a reviewing committee would care about. All that's important is that your credentials were strong enough to earn you the internship. Whether you were paid or not is irrelevant to the strength of your credentials.