Awesome podcast 由 爬坡道, 小山 Guo (who lives in Shanghai). Each episode focuses on new vocabulary, pronunciation and comprehension. 显示 now has over 40 episodes and counting.
Very nice tutorial in 30 parts that presents basic vocabulary. Audio clips are included and the corresponding written character is displayed. 你 can click a button to see a brief 动画片 that shows the stroke order for the character.
Handy little reference 表 that allows 你 to click on a Zhuyin (bopomofo) symbol, hear the correct Mandarin pronunciation and see the pinyin equivalent. Very useful for those needing to use 或者 crossover between both phonetic systems.
Basic vocabulary is covered on this site. Many of the pages 显示 图片 of related objects (e.g. things in a living room). Mouseover to hear the pronunciation.