Between the Clouds - This (31 Day / Complimentary) "Rudder" attempts to weave the Christian contemplative tradition seamlessly with developmental psychology, anthropology and physics.
Busted Halo - Sponsored by the Paulists and written by young adults for young adults. Includes discussion boards on various topics, a Flash trivia quiz, guides for seekers.
A Cry of Love - A meditation on the Passion, told in the first person.
Daily Virtual Retreat - One-way (read only) electronic mailing list. With different themes for each month. Short Scripture quotes and comments provide food for further meditation for each day.
Invisible Monastery - International, multilingual online group of Catholics who believe in the power of prayer, and who commit to praying weekly for each other's special intentions.
Listening to God in Prayer - Booklet by a Filipino Opus Dei priest teaches a simple way of prayer as a conversation with God.
Online Ministries - Includes daily reflections on readings for Mass, an online retreat, tips for praying, and Stations of the Cross. Based on Jesuit spirituality. From Creighton University.
Pray with the Heart - Litanies, novenas, the Way of the Cross, and other Catholic prayers.
The Spiritual Exercises of St. Ignatius of Loyola - A classic. The Ignatian method of prayer uses visual imagination to draw nearer to God. Intended for spiritual directors or retreat masters, but "directees" can benefit from this book as well.