JinnIde is a plugin that allows using Jinni Prolog, now also hosted here on this site (with open source license!), within the confines of an IDE integrated in JEdit.
XGP is an integrated development environment that extends GNU Prolog to work with Cocoa under Macintosh OS X. It provides user interface and graphics facilities largely compatible with MacProlog32 by LPA. Requires Mac OS X version 10.2.1 or greater.