Also "Bardo Teachings" by Lama Lodro and probably Trungpa Rinpoche and Francesca Freemantle's "The Tibetan Book of the Dead", both available at Amazon, Snow Lion, Wisdom Pubs. Also look and see if HE Thrangu Rinpoche has published open teachings on the bardo.
There is also Sogyal Rinpoche's "The Tibetan Book of Living and Dying" which is in part Sogyal Rinpoche's presentation of the Bardo Thodol and it's teachings to his students. I found it useful when I moved from Zen Buddhist to Tibetan Buddhist practice as he introduces a very basic phowa practice that people can use without empowerment. You might also want to give Professor Thurman's translation of the Bardo Thodol a shot - his commentary is probably very good but his translation is idiosyncratic and unusable IMO but he did that to make the root text that he translated more accessible to Western English readers.
Then of course it would be best to take these teachings from a lama and go on a phowa retreat.