Mmmm, tamales. I used to get them from my students in south Phoenix at holiday time. However, the first time, I didn't realize that you don't eat the husks... well one bite made me figure out that you open it and eat it. Score one for the stupid white girl from Boston.
The lard is mixed in with the masa. That's what makes it taste so good. However, I am sure you could substitute another fat, but it wouldn't be authentic.

Now I will be craving tamales all night.