Jewish Music Websites

Chabad.org - Jewish Music and Song
Dartmouth Jewish Sound Archive
Invitation to Piyut
Jewish radio shows and podcasts - Annotated list on "Klezmershack"
Judaica Sound Archives (Recorded Sound Archives - Florida Atlantic University)
Online Heritage (Jerusalem National University Library – The National Sound Archives)
Ruth Rubin Legacy: Archive of Yiddish Folksongs (YIVO Online Exhibition)
Save the Music
אוצר הזמר העברי [Treasury of Hebrew Song] - Site of songs held in the IBA [Israel Broadcasting Authority] archives, including songs in Yiddish, Ladino and other Jewish ethnic languages
זמרשת [Zemereshet] - Early Hebrew songs 
לילות טובים - Internet radio with comments in Hebrew

Ethnographic Sites and Collections

AHEYM: The Archives of Historical and Ethnographic Yiddish Memories
- Videos on Youtube of the Yiddish-language interviews associated with the AHEYM project
Fortunoff Video Archive for Holocaust Testimonies
- Songs from the testimonies:
Volume 1: Where is our Homeland?
Volume 2: Cry, My Heart, Cry!

Music in the Holocaust - Sites

Fortunoff Video Archive for Holocaust Testimonies
"Heartstrings" - Music of the Holocaust (Yad Vashem) 
Music and the Holocaust (Ort)
Music and the Holocaust (YIVO)
Music of the ghettoes and camps (FCIT)
The Stonehill Jewish Song Collection (songs recorded by Holocaust survivors)
United States Holocaust Memorial Museum

 Blogs and Personal Sites

A good resource for blogs to is "Teruah" (see below). Here are a few of my favourites:
Candles of Song: Yiddish poems about mothers
Dumneazu - Bob Cohen  
Eshkol HaKofer - History, culture, and religious significance of Henna art
Jewish Morocco - Rare music, travel, and other thoughts on Jewish Morocco
Shirim Khadashim: New Jewish Songs - George Robinson
Jane Peppler has several blogs, the most recent of which is Polish Jewish Cabaret and Yiddish Penny Songs.
Teruah - Jewish Music Blog
Yiddish Song of the Week
YIVO Sound Archives

Radio and Podcasts

The Yiddish Voice