Distribution lists in Outlook will allow you to send the same email to multiple people at the same time.
In Outlook 2010 and 2013 a distribution list is referred to as a Contact group.
Click the Contact link (or People link in Outlook 2013) and click New Contact Group at the top of the screen.
Click into the name field and type a name for the group and then click the Add Members button and choose where you want to add the names from e.g. Outlook address book.
Select the names that you want to add by double clicking on each of them, when all names have been selected click OK.