Anyone using a Cisco 2811 as a PRI-SIP gateway?

I was wanting to virtualize a FreePBX installation, so I would have to convert my T1/PRI to a SIP with a gateway, or so I presume. I have a Cisco 2811 that isn’t being used any longer, so what I’m looking for is a good config for this that would work with FreePBX. Otherwise, I don’t know where to begin. Any help is appreciated. (I’m fine with a sanitized config.)