Workzone - Workzone is a web-based project management software.

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

Milestone Planner - Visual project planning tool. Powerfully simple. Quickly build and share professional milestone plans on-line to track deliverables - Free sign up.

Recurly - Subscription billing and recurring billing management. Recurly offers enterprise-class subscription billing for thousands of companies worldwide.

Xebrio - A Project Management Software to Fulfill Your Story From Requirements to Deployment.

Zuora - Zuora creates cloud-based software on a subscription basis that enables any company in any industry to successfully launch, manage, and transform into a subscription business.