It's not possible to change the From email address using Vlingo. Vlingo always uses the default email account configured in the iPhone settings to send.
You will need to make the following changes in your phone's settings (not Vlingo's) to send from a different email account:
- Find and click on Settings application on your iPhone.
- Click on Mail, Contact, Calendars.
- Find and click on Default Account.
- Select the account you want to use from Default Account.
- Close Settings to save you changes.
- Now launch Vlingo and compose a new email.