Depending on what you want to do, test or learn with the lab, the configuration will change.
I suspect you are doing some training, in which case have a look on the Cisco website, and you will find many different scenarios that you can copy and learn from.
First thing is to check you have the correct copies of CallManager on the routers, otherwise you are not going to get very far with this.
Agreed… Ensure you have what you need as far as the CME engine and DSP’s go. To set up the phones to talk to the router for DHCP/TFTP/SCCP services, you most likely will need a switch to connect all of your phones to your routers properly.
The Cisco 2960 supports most – if not all – of the configs needed for your VOIP Lab.
Also, for VOIP basics, Cisco’s packet Tracer 5.1 and later will allow you to build a virtual VOIP / CCNA-V lab – albeit limited…