These are products, both commercial and open source that are built using PGSQLKit:
Products
Chatty Home
Chatty Home Server App
ChattyHome is an Arduino, MySQL (but soon to be PostgreSQL), Cocoa based DIY attempt at creating an intelligent house system. Another words, it’s home automation for Mac.
Recently migrated to PostgreSQL using the PGSQLKit, Piotr ‘ghrom’ Farbiszewski has built an intelligent and impressive system for Home Automation on the Mac platform.
Two Wheel Junction
TwoWheelJunction.com is a website and community by riders for riders. It is not about a specific type of bike, but for and about the more general class of all riders.
The website itself, and all of it's administration tools are written in Objective-C and use the PGSQLKit as the library of choice for powering the site.