I am a long time lurker on this forum and I am making some resources to learn and listen to the Vietnamese tones. These are very difficult for the English-ear, so, I made a blog with audio recordings.
If you want to see/listen as well, please reply asking so. I don't want to spam this awesome forum with promotional material, so if anyone wants the url, please ask. It isn't a money-maker or anything, just a passion project.
I plan on making some audio-flash cards as well, to test my hearing, but I need to learn php first