http://www.freshbooks.com/

FreshBooks provides fast and simple invoicing and time tracking services that help you manage your business.

Secure, web based tool branded with your business name.

• Invite contractors to join your team and track time on projects. Receive their invoices all in one place. Logins for contractors and staff.
• Share documents with your staff and clients, set access levels to restrict who can see what.
• Create support tickets to help manage additional time spent with customers.
• Send invoices by the mail prepared by the FreshBooks team, just purchase stamp credits. Invoices are sent via first class business mail within one business day.
• Keep track of your expenses, for both projects and yourself. Easily re-bill clients on project expenses.
• iPhone app for remote use

Fresh Books has tons of add ons in the following categories:  mobile, time tracking, project management, accounting, expenses, CRM, forms and appointments, marketing,  eCommerce and POS, Google document sharing,  WebHooks,  payment gateway,  electronic signatures and customer support

FreshBooks has 5 different paid plan options and 1 free plan. The free plan has many bells and whistles, but you are limited to 3 clients but you can invoice them as much as you need. Also, emails sent from the system will have an added signature at the very bottom that reads: “Save time invoicing with FreshBooks (www.freshbooks.com)“.