I normally use the gmail app for email, but when I looked at the "Messaging" app, the email icon was not there. I had facebook, twitter, and text messaging, but no email account. I do have the google account present in "My Accounts." What could have happened to the email app in the messaging app?
I had the same question when I got my DroidX. From what I was told, Gmail has it's own icon in My Applications. If you want to add it to the Messaging App, you will need to add it as a regular POP e-mail account.