ChargeOver - ChargeOver automates recurring billing, subscription billing, & payment acceptance. A SaaS that integrates with Xero, Quickbooks, & has an API. Free trial.
GnuCash - A personal and small-business financial-accounting software, licensed under GNU/GPL and available for Linux, Windows, Mac OS X, BSD, and Solaris.
Elorus - A super-easy online invoicing & time tracking software
Xcalibur - Control, and process data from Thermo Scientific LC-MS systems and related instruments
MinuteDock - Web-based time tracking software designed to integrate with the Xero accounting package.
Analyst - Instrument control, data analysis, reporting, and audit trail for SCIEX Mass Spectrometer systems.