Online Chinese Classes
Online Classes from Instructor Rosa Yeh
BBC Mandarin Chinese Language Site
The BBC has a wonderful collection of useful sites for learning Mandarin.
BBC's introductory slide show
From an unofficial page at Rutgers University
An online course from Tenafly NJ
Here are some songs that were recorded in China probably in the late 1930's or early 1940's. As the labels are in Chinese I can't provide any further information.
Song 1 and 2
Song 5 & 6