If you’re Vietnamese or learning to type Vietnamese language using regular US keyboard or so, you might have come across this software program call VPS Vietkeys, by Hoi Chuyen Gia Vietnam something, I noticed that they don’t like Communist Vietnamese and they blocked all IP from Vietnam accessing its site. The VPS software made available by their team is great, but for some reason, their program no longer available to download or access much information about it. If you go to vps.org and try to click on VPSKEYS and click on download or something or from there you would get a message to contact them. So I don’t know what’s going on, political reasons probably.
Anyhow, if you’re still looking for this software and want to use it, there are archive on the internet, just search for it on google.com type in “download vps vietnamese typing” or something similar, there should be mirror site or site that have the file for you to download. Or go here http://batkhuat.net/kt-dl-cachdung-vps.htm