I made a happy little discovery today.
I've known how to flip 2 edges for a long time using Mi Ui Mi Ui Mi d2 Mi Ui Mi Ui Mi d2. This flips UF and UB, and with setup moves can flip any two edges.
But today, I discovered that I can also flip two edges using the Up-Replace-Down 3-Cycle twice. It came about quite by accident as I was fiddling with the cube. I haven't mastered it. Maybe if and when I do, I'll explain more.
(12/4/09: I guess I never mastered it. Why not? It would take more turns and more thinking to accomplish the same thing as the algorithm above, so the only advantage would be if you were trying to solve the whole cube using Up-Replace-Down. Besides, there is a different method for flipping edges that I got turned onto somewhere along the line that I like better than the above algorithm. It involves moving the edge to a different layer, then putting it back into its slot from a different angle. Then you move the other flipped edge to that spot and retrace your steps.
With the Jing's Pyraminx puzzle it took me awhile to figure out how to apply the principle of flipping two edges, so in the meantime I 3-cycled them out of place and then back into place correctly oriented.)