PracticePanther - PracticePanther offers CRM, invoicing, time tracking and communication solutions for law firms.
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.
PHC FX - PHC FX is a comprehensive solution that offers a wide range of functionality at any price.
ChargeOver - ChargeOver automates recurring billing, subscription billing, & payment acceptance. A SaaS that integrates with Xero, Quickbooks, & has an API. Free trial.
iDempiere - iDempiere Business Suite ERP/CRM/SCM done the community way.
Elorus - A super-easy online invoicing & time tracking software