Here's a list of sites where you can find prayers, poems and quotes. The following resources are inclusive and multi-cultural, representing various faiths and beliefs.
Search the sites for prayers and readings to use in your ceremonies or perhaps be divinely inspired and create some of your own.
Word Prayers.org describes their site as; “World Prayers - Gathering the great prayers from all spiritual traditions around the world into a unified nonprofit archive; for the purpose of inspiration, study and cross cultural appreciation.”
Gratefulness.org proclaims their vision to be; "A worldwide community dedicated to gratefulness as the core inspiration for personal change, international cooperation, and sustainable activism in areas of universal concern."
Todays-Weddings.com is a wedding directory site that has info on all facets of weddings. They have a section with prayers and readings that is very helpful, it lists many religious readings, poetry and other quotes from literature that would be appropriate for using in wedding ceremonies.
Spirituality and Practice
Spirituality and Practice.com website has a section of love quotes that you may find useful for ceremonies.