I'm no wine expert, but the ones I've met stress the importance of aeration, or 'breathing', to get the full flavor out of your aged potions. Particularly reds.

Aerating usually takes awhile and requires some separate glassware-type equipment.

Menu comes to the rescue with their line of Decanting Pourers & Aerators. You simply insert the cool, black rubber stopper end into your bottle, and the device, using some smart design, aerates your wine as your pour it into your glass. The spout is designed to be drip free (no more streaks down the bottle!).

Reviews are remarkably good, and mine should arrive in a few days so I'll let you know my thoughts :).

Just so you know (no site seems to say this) there are 3 versions sold (in increasing price order): Selection, Vignion, and Premium. Selection is all plastic (acrylic) so you can see the air+wine mixing action. Vignion simply has a nice stainless steel base, while the Premium model has plastic to see the mixing with a solid, stainless steel funnel end.

As far as I've heard they all work the same. The different versions are just for design purposes (and priced accordingly). You can see pics of all three and a graphic illustrating how they work with the 'Take a closer look' button.

UPDATE: Got the 'Selection' model and tried it on a simple bottle of Cabernet Sauvignon I knew well. It works! After pouring through the gizmo, the dense, heavy Cabernet was separated a bit into its constituent flavors, for more detailed tasting and enjoyment.

great idea...takes mess out of regular handheld aerator