I'm a consultant and have been using quickbooks online for years for invoicing and managing my accounting. They have been down all day today (isn't the first time either): https://qbo.intuit.com/c27/v0/offline.shtml
I've never been very happy with their service, but have been unable to find a decent alternative. For example, until recently their "web interface" was only compatible with IE. Now they have beta support for Safari (works ok), and Chrome (doesn't work well). Their web interface is really old school, slow and clunky.
Does anyone know of a decent, low cost web-based accounting system for a small business? Something fast and easy to use like mint.com, but for business (i.e. invoices, sales orders, income statements, credit card processing, etc.)