This addon is suited for small businesses who already use Microsoft Outlook to help manage their day to day work. It helps extend features in Outlook to intuitively work with Xero.
Outlook Integration Tools - QWD + Xero
When you install the addon, there will be several new ribbon menus available within Outlook. Simply connect to your Xero Account(s) and you'll be able to sync contacts, send invoices, use calendars for timesheets and/or billing plus much more.
To get started, simple download the addon from here: http://www.quickwindevelopment.com/addons/outlook-integration-tools/