I know a little bit of mandarin already, so I decided that this app might help a bit. However, there are no voice pronunciations, nor does the app show you visually how to pronounce them, which probably will result in an extremely thick American accent. For example, thank you spelled in the alphabet (and shown in the app) would be Xie Xie. Newcomers would pronounce it as SEE-SEE, but its more like Shh-yia Shh-yia (I might not be perfect on the real pronunciation though due to my instructor having a Changsha dialect).
Truely impressed about Speak Chinese!, v2.0