Sephardic Music: A Century of Recordings is a discographic website charting the recording of Sephardic secular and liturgical songs. It includes great sections on 78 rpm recordings, early repertory, and modern recordings. Samples of songs are littered throughout, but many can be found in the Appendix section on 78 labels (at the bottom of the page) and the Songs section of the Appendix. There are many other parts of the site to explore, but the Bibiliography deserves a special mention, as does this page providing samples of 125! different recordings of the popular song A la una over the past 100 years.
Who are the Sephardim? provides a short history of Sephardic Jews. The Ladino language website has a more complete introduction to Ladino, the Judeo-Spanish language. Included are a brief descriptive grammar, stanzas from Joseph the Wise, a long Ladino poem, and a translation of The Story of Gerineldo, a folktale. There are very good primary sources at the Medieval Sourcebook, and a Yahoo Ladino discussion group. This essay about the interactions between Moorish and Jewish cultures and their collective effect on European culture seems quite good (and is in Spanish). See also this Spanish-language article about exploring Ladino. There are more good Spanish-language resources on Sephardic history here.