The Lotus and the Cross
I especially like the chart comparing parallels between the Buddha and St. Francis of Assisi.
I just finished reading the book Christian & Islamic Spirituality: Sharing a Journey, by Maria Jaoudi, which makes comparisons between St. Francis and Rabi'a, the 8th-century female Sufi mystic. Rabi'a's writings do indeed sound Franciscan:
Whenever I listen to the voice of anything You have made--
The rustling of the trees
The trickling of water
The cries of birds
The flickering of shadow
The roar of the wind
The song of the thunder,
I hear it saying:
God is One!
Nothing can be compared with God!
Perhaps St. Francis can serve as a gateway to dialogue with other religious traditions.
Jon's website also has one of the best articles I've ever read on panentheism: The “Everywhere-ness” of God—God in All Things. (Karen Armstrong refers to herself as a "freelance monotheist," so I'm going to start referring to myself as a "freelance panentheist.")