4S mail question

Is there any way to set up mail folders other than INBOX, SENT, and TRASH with my pop email account?

Not really no. You need an IMAP style email account (like gmail) for the folders to pop up automatically. I would really suggest moving over to gmail if you're a mac person (especially if you're an Ios person). You can auto import your old email into your gmail and that way you don't have to tell everyone you have a new email...