This may or may not be a stupid question, lol. I just bought my first blackberry off of ebay and received it today. So far I love it but the only problem is that whoever owned this previously did not delete his email account. It seems that he has both a yahoo and gmail account on it. How would I go about deleting his accounts and adding my own? Thanks for your patience, Im a newbie

first go options - advanced - service books
and delete any that have an email address followed by [CMIME] and [CICAL]

Thank you! Now that those have been deleted how do I add my own Yahoo account?

do you have the blackberry data plan on your account?
If so you can do it by going to the setup folder - email setup.
If it only says enterprise option not personal email, you can do it on a pc, from the Sprint BIS page.

Welcome to the forums.

The FAQ is a great resource: How to add / delete email addresses - BlackBerryFAQ

Thank you. I may just take this into the store to figure it out but since the phone was previously owned, when i tried to make an account it said there is another account associated with this pin. Any ideas?

Yup, the previous owner hasn't deleted their BIS account, and you cant register it, until they cancel theirs.
Talk to the previous owner.