Does anyone have a tutorial, or could explain here, how to create billboard leaves (like those SpeedTree uses - the leaves will always face you).
I’m using 2.49b.
I would really appreciate it, thanks.
I really haven’t made leaves using Billboard but I have some idea. You need to combine these two tutorials: one on texturing Billboard, and one on instance Painting to make bunch of leaves.
Great, thanks 
I imagine if you create a leaf with an alpha background and apply it to a plane that will give you a leaf to view.
Then constrain it to always face the camera (in 2.57 that is [Ctrl][T] and choose the constrain type). You chose the -leaf, in this case- Then chose the Camera, Then hit [Ctrl][T] to constrain. … sometimes I get that turned around though so it might be the camera Then the leaf.
The way I read your question is; ‘How do you make a leaf sprite?’. I hope this helps some.