Mixing 2 actions in one

I have to actions for player(walk forward and walk left) and I want to mix them 50:50 when player walks diognally left/forward. How do I do it?

at the action actuator, you need to play with the layer setting. example, action 1 layer 0 action 2 layer 2
and use the blend setting to blend the animations. set it to the frames you want to mix

Does it allow things like aiming and running at once?

yes it does, the layer is the one ur most intrested in, it sets the layer witch the action is playing on.

Are there any tutorials around?