Mail in iOS 6 (and Mountain Lion for Mac) features a VIP inbox to collect messages from people that you definitely don’t want to miss. It’s similar to Gmail’s Priority Inbox, except instead of hoping your email figures out which messages are important, you can specify who is important.
The VIP list syncs over iCloud between your iPhone, iPad, and Mac and works more like a Smart Mailbox—it’s really just a different view of your real inboxes that shows just the messages from people you mark as VIP.
To view your VIP inbox, tap the Mailboxes button in the upper left until you see the Inboxes view, then tap the VIP inbox.
To add to your list of VIPs, tap the blue arrow on the right of the VIP inbox label. On the next screen, tap the Add VIP button to view a list of your contacts, then tap any contact you deem worthy of VIP status.