What you'll need is a pot of simmering water, an egg, a small cup or bowl, and microwavable plastic wrap.
Bring water to a boil then reduce to a simmer. Use a small bowl or cup and push a piece of plastic wrap into the cup.
Crack an egg into the plastic wrap and tie the top with a small strip of plastic wrap or a piece of twine.
Gently lower the egg into simmering water.
Poach in simmering water uncovered: 3 minutes for runny yolks, 4 minutes for slightly firm runny yolks.
Use a fork or tongs to fish out the egg and gently slide the egg out of the plastic wrap.
I was a little hesitant about using the plastic wrap but it did not melt so it seems fine to me. One way to minimize the time the egg spends in plastic wrap is once the white has solidified enough, you can cut the plastic wrap and slip the egg out into the water but I haven't tried this. If you have health concerns, there are other ways to poach an egg.
Elise has another poached egg trick on her blog Simply Recipes.