So what i have found and it might make others feel more at ease.
I have a small utility application on original MacPro and just installed Snow Leopard which told me I need to install Rosetta and would I like to now download and install it.
So I did and the application works. This may not be the case for the newer Mac pros I do not know but if you have an original or the second generation I believe you can use some applications that you might have thought would no longer open in Snow Leopard.
I find it interesting that they set it up so it downloads and installs and you do not have to restart the computer in order to use it.