The guys over at MessageOps have a posted a step-by-step guide on how to send an email using a secondary email alias on your Exchange Online mailbox: http://www.messageops.com/blog/index.php?/archives/25-Sending-as-secondary-alias-in-Microsoft-Exchange-Online.html
Tag: Outlook
Configuring Outlook without using the Microsoft Online Sign In client
Jeff Schertz over at PointBridge has a great walkthrough on how to configure Outlook to connect to Microsoft Online without using the Microsoft Online Sign In client: http://blogs.pointbridge.com/Blogs/schertz_jeff/Pages/Post.aspx?_ID=88