Recently came across a QR Coder [1] that can generate for a variety of different purposes, including Wifi (e.g., Bookmarks, Email, Contact, GeoLocation, SMS, URL link, etc.) - the same website also has a encoder/decoder and an API [2], but I've not tried those features.

[1] http://niftypdf.com/Barcoder/QRCoder [2] http://niftypdf.com/Barcoder/API