Ah, it's difficult to explain, since (as far as i know) only scandinavian languages have that sound..http://translate.google.com/#sv|en|ä%20ö%20å you can click on the "listen" button to hear the pronounciation :)

å 哦（一声） 嘴巴非常的圆 舌头放低 长音 ä 哎（二声） 嘴巴有点瘪（两边宽） ö 额 （差不多相似吧，但是是长音） o 乌 （也是长音）

hmm,. my swedish friend has told me when he was in china, but i forget x( sorry