Is there a version of Mail for OS 10.6.8 ?

Mail is a built in application. Not sure what you're really asking, maybe you could expand on that.

I think version 4.6 comes with Snow Leopard.

If this matter came up following an application of a security update, you might like to look at 'More like this' >>>>> to the right of your initial post. And don't overlook the links within the threads.

There are several references to Mail problems ... and solutions too.