http://www.virtualmoney.com/millenniumdollars.html

Since there is no guarantee on the liquidity of this private currency and there is no way to identify the sellers of this currency its not clear whether or not this is simply a scam, or if it is an honest attempt (and almost certainly a failed one as it seems bizarre to me that you would try to create a "real Currency" and back it with US Dollars) to create a meaningful private currency. Either way I would not be buying.

If you are interested in private currency I think Liberty Dollars http://www.libertydollar.org/default.asp are a more interesing project. these are supposedly backed by silver. Supposedly they are audited by a CPA, but I don't put a lot of stock in that audit simply because I do not know the credibility of that firm, what assets or insurance it has to back it.