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This product ranks as the "Find of the Year" for us. You can do everything from generating automatic invoices that can be hands-free "snail mailed" or emailed to managing projects or quotes. They even have blll paying on their site for your customers and it automatically logs it into your books. Check out the RSS feed for an up-to-the-minute report of all things happening on your account. For programmers it even has an API for extending it into your own site. If there is anything better out there then I don't know what it could be!