and I don't know what 'mailhost' means for VERIZON
A little checking (search for "verizon wireless email phone" got back (among others): http://forums.mobiledia.com/topic59804.html:
Your phone's email address is (your mobile phone number)@vtext.com.
Therefore, your mail host would be vtext.com.
Correction: (I read the question wrong)
Mail host is your mailer (for google mail it would be imap.gmail.com if that is where you send mail from. Local SMTP servers may vary as to name.
If the mail server is not under your control, check with the administrator responsible for a user name, password and SMTP server name.