QuestXpress

 http://www.questxpress.com/

Once it is set up it works great.  You can transfer invoices into QuickBooks.  You can also you it for your clients.  An all in one system.  Enter orders, track them, store images, create invoices and send scanned searches to your clients.  You can access anywhere you have internet connections and your clients can also track their orders and download them once completed.