Programs should include English translations of all foreign-language vocal texts. Don't forget to identify both the translator and the author of the original text! In most cases, published translations -- including those found on the internet -- are protected by copyright, so permission should be sought before including them in your program.
Ideally, singers should prepare their own English translations, if their foreign language skills are up to the task. While it's tempting to copy translations from books or websites, doing so without crediting the actual translator is PLAGIARISM.
If you need them, the Music Library has many books with original and translated texts of art songs, opera, and sacred music. Most are shelved in the reference section. Here's a small sample:
Schubert: Complete Song Texts, with translations by Richard Wigmore. ML54.6.S39 W52 1988
Lieder Line by Line, and Word for Word, by Lois Phillips. ML54.6.P55 L5 1996 (REFERENCE)
Masters of the French Art Song: Word-by-word and Poetic Translations by Timothy LeVan. ML54.6 .M33 1991 (REFERENCE)
Masters of the Italian Art Song: Word-by-word and Poetic Translations by Timothy LeVan. ML54.6 .M34 1990 (REFERENCE)
Singer's Anthology of 20th-century Spanish Songs... with translations by Josep Sobrer and Edmon Colomer. ML54.6 .S563 1987 (REFERENCE)
Ring of Words: An Anthology of Song Texts, translated by Philip L. Miller ML54.6.M5 R5 (REFERENCE)
Italian belcanto opera libretti with ... word for word translations by Nico Castel. ML48 .I882 2000 (REFERENCE)
Libretti of Mozart's Completed Operas with ... word for word translations by Nico Castel. ML49 .M83 C3 1997 (REFERENCE)
Handbook to Bach's Sacred Cantata Texts: an interlinear translation... by Melvin P. Unger ML54.B15 C329 1996 (REFERENCE)
Don't forget to check the notes that come with CDs. These almost always include translations. But don't forget to credit your source!