ChargeOver - ChargeOver automates recurring billing, subscription billing, & payment acceptance. A SaaS that integrates with Xero, Quickbooks, & has an API. Free trial.
Xero - Xero is online accounting for your small business.
BillGrid.com - BillGrid is an easy to use online invoicing, billing and expense management system that will save you time with tracking clients projects, expenses, invoices and payments.
Datamolino - Process all invoices without retyping. We turn your invoices into structured electronic documents, that you can import directly into your accounting system.
fusebill - Fusebill is the leading recurring billing and subscription management software for businesses. Try Fusebill for subscription billing made easy!
DOKKA.com - The Future has Arrived: Accounting Process Automation