Freshbooks is essentially an invoicing system; An easy-to-use program that allows you to create clients, estimates, and invoices in minutes. Depending on the level you choose, you can add staff to make their own invoices, create reports and time sheets (hello, instant sales tax report), and manage multiple clients at a time. While we don't use it this way yet, but you can actually use the program as your time tracking device if you're a service (time) based business too.
Since we can instantly email out our invoices, print pdf copies for our files, and give our clients the choice to pay by Paypal or via check, we have already received rave responses from our brides that have used it. And, bonus: if you have an iPhone you can also download the Minibooks app (use the Lite version if you want it free) to invoice and see your invoices on the go too.
What invoicing systems do you use? Do you have any tips to share with us? Do tell!