How to set up e-mail for clients if I am hosting their site?

I have been making wordpress sites for some friends and family members. I just host their sites for them on my hostgator account. They are starting to refer me to other people for web design, and I am trying to figure out how to handle e-mail accounts for future clients if I am providing the hosting. What do I do if they want to change the password for their e-mail address so that I won't know what it is?

Sounds like you need a reseller account http://www.hostgator.com/resellers

Jazzc, that is exactly what I was looking for. I feel a bit stupid for not discovering that myself. Thank you!