VOIP configuration on HP 3500 switch

Hello All -

I am in the process of deploying a VOIP system. I will be using an HP 3500 POE switch for the phones as well as the workstations. I am planning to have all 48 ports in the native VLAN. Also, I will have ports 2-22 on VLAN 10 (which is configured for Voice. We only have 20 phones). All the workstations will be connected to the phones. Ports 2-22 will be tagged and ports 1,23-48 will not be tagged.
The signaling server for the VOIP phone is in another subnet. We will be using a Cisco 1841 router to connect to that subnet. Following are my questions:
1.) Do I need to configure ports 2-22 as trunk ports using 802.1q encapsulation?
2.) Should I leave ports 1, 23-48 as access ports without modifying anything?
3.) What configuration would I need to do on the router to make sure voice packets get routed across the WAN? Router has 2 FE interfaces.
4.) Should Qos be configured on the switch or on the router or both?

Any help would be greatly appreciated!
Thanks!