The Call Center app allows you to manage call queues.

Call Center exposes agent, manager and administrator settings so that you can enable end users to use call queues as efficiently as possible. Developers/admins can use the queues in callflows (visual or via API) with all other elements in the system. When creating a call queue, administrators have the ability to choose the most effective call routing strategy for their needs, along with personalized hold music and a separate escalation queue if desired.
Features:

• Call queues
• Detailed view for agents to: Log in and start taking calls, See who else is in their queue and what is occurring, Log out or mark themselves as away, See real-time statistics on their daily performance.
• Queue metrics