AsteriskBilling.com - General technical and billing information for VoIP operators using Asterisk PBX.
The purpose of an Asterisk Billing application, aside from the billing portion, is automation of provisioning. Automating the Asterisk provisioning is crucial so both prepaid and postpaid accounts can be provisioned and unprovisioned based on the user's billing status. At the minimum, look for a billing solution that can provisioning SIP and IAX protocols in Asterisk.
If this functionality is not included in a billing package, the ability to scale is restricted to the time resources a company has available for manually provisioning new accounts in Asterisk.