For those Vietnamese people among you guys (okay, fine, not too many of you): I've just finished developing a conversion utility that allows you to convert from Vietnamese legacy formats such as VPS, VNI or Vietnet into Unicode. This utility is also helpful in decoding those gibberish emails that resulted from incorrect Vietnamese unicode settings (use the Unicode UTF8 or Unicode HTML source format in this case).
The web-utility is available here:
http://www.enderminh.com/minh/vnconversions.aspx
I also make the .NET XML web service freely available here:
http://www.enderminh.com/webservices/VietnameseConversions.asmx
I just finished coding this, so I can imagine that it's still a bit buggy. Just report those bugs to me, and I'll fix it.
VPS
Vietnet
Converted into Unicode
Have fun!