Creating Custom Key-bind for an action (ie. consecutive button presses)

Basically, I want to assign a key (lets say F5) to the action " s, x, 0 " so I can simply press F5 to align my verts along the x-axis.
And do the same thing with F6 for the Y-axis and F7 for the Z-axis.

I cant figure out how to do this - anyone have a solution?

You need to create an operator (ie, a python script addon) which does the sequence of actions you want, then assign a hotkey to run that addon.