QuickBooks is a powerful small-business accounting package, but it doesn't always do everything a business needs--or do it well. To the rescue: Third-party developers--a whole slew of them--have created Web services that integrate with QuickBooks to address specific problems. The 10 add-ons here can help small businesses with everything from fine-tuning strategy and automating aspects of inventory management to setting up a store in Facebook, lowering shipping costs, and more. All are either free or reasonably priced; you can get them and many more add-ons through the Intuit App Center. Many are Flash-based. These tools work with either the QuickBooks desktop software or the online version or, in some cases, both.