I’ve been using Moose Mitts since the beginning of December. AFAIK, they are the only drop bar compatible pogies available.
(Correction: I see that there is also a product called “Bar Mitts” out there.)
This is what they look like from the side:
On my bike, the left one droops a bit because I don’t have a gear cable coming off the left side of the handlebar.
These mitts have three points of attachment. There is a velcro wrap around the handlebar on the inboard corner of the mitt. There is also a slot to accommodate the gear cable that Velcros shut around it. You can see the slot in the above photo where the purple lining is visible.
From the back, you can see the third point, which is at the bar end. There is plenty of room inside the mitt to use all possible hand positions (although I should state that I mostly ride on the hoods).
The attachment at the bar end was originally a small piece of elastic. It is still visible on this photo on the left side. (and you can see it in the images on the manufacturer’s website.) The elastic on the right side came unstitched after a day or two of use, so I put a piece of Velcro One Wrap on each side. The width of the One Wrap makes the attachment point much more secure than stock.
(as an aside, Velcro One Wrap is a great product that is useful for all kinds of things both on and off the bike. Imagine a wide, infinitely reusable cable tie)
Bottom line: in weather down to -10C, I’ve been able to stick with a thin pair of windblock fleece gloves for my half hour commute. Highly reccommended, if a bit pricey.
There are many other pogies out there for non-drop bars. There are even two companies in town. I met the people behind these products on last year’s “Coldest Day of the Year” Ride.
The developer of the “Barbra” is standing to the right in this photo.
UPDATE: Handlebar booties has a website that appears to be dead (Nov 2016).
2014 update: I switched to Handlebar booties on my new winter bike (which doesn’t have drop bars). They are still being sold at Urbane.