Version 1.3 of IFTTT adds a new iOS location channel that you can use in any recipe. This location feature allows you to setup a geographic fence that'll trigger an action when you enter an area, exit an area or do both.
Besides a standalone channel, Location is also pre-built into existing channels like Instagram, Facebook, Foursquare or Twitter. This allows you to send out a message when you take a new Instagram photo in a particular area, for example.
The updated version of IFTTT is available now in the iOS App Store. I've already created a few location-based recipes, and love the feature.