QuickBooks integrates with Xsilva's Lightspeed Point of Sale product. To use, you must purchase a copy of Lightspeed and follow the instructions included with the Lightspeed software to integrate with QuickBooks.
Each time you open QuickBooks, it checks for new transactions and then imports them.
Note: If you use multiple QuickBooks for Mac company files on a single machine AND created some of those company files from the same original company file (like using a company file as a template for others), you may have a problem with the importing transactions into the right company file.