ChargeOver - ChargeOver automates recurring billing, subscription billing, & payment acceptance. A SaaS that integrates with Xero, Quickbooks, & has an API. Free trial.

Sage Intacct - Intacct is a cloud-based accounting and financial management system that is designed for the businesses of all levels.

fusebill - Fusebill is the leading recurring billing and subscription management software for businesses. Try Fusebill for subscription billing made easy!

Chargebee - Chargebee lets you manage subscriptions and payments at scale, handle custom recurring billing scenarios, reduce subscription churn and simplify accounting.

MinuteDock - Web-based time tracking software designed to integrate with the Xero accounting package.

FinancialForce Financial Management - FinancialForce.com provides cloud back-office applications for Salesforce CRM.