As those of you already know, the Unihan database at
http://www.unicode.org is available for download in their public ftp site which can be accessed via their website. As KoboDaishi asked me a while ago for a listing of Vietnamese readings, I've extracted the readings from the unihan.txt document, and zipped them up for you to download from my website at
http://www.dylanwhs.ukgateway.net/misc/index.html
There are some readings which have characters which did not come out properly in the download, and I've not fixed it. There are over 8200 entries with some characters in Extension A and others found in Extension B, mostly having one reading, but some characters have two readings.
Cheers,
Dyl.