FreshBooks - The ideal accounting software for small business owners.
Clio - Clio provides a full suite of web-based practice management tools targeted specifically at the administrative needs of sole practitioners and small firms.
Avaza - Beautiful Projects, Timesheets, Expenses, Quotes & Invoices for Small Businesses
MyCase - Practice More, Manage Less.
Moon Invoice - Free Invoice Generator App - Easy Invoicing Software - Fast Mobile Invoicing App
PracticePanther - PracticePanther offers CRM, invoicing, time tracking and communication solutions for law firms.