Brickset members have already started to compile the 'dot code' sheets for the Series 4 Collectible Minifigures. There two such sheets currently available...
The first can be found on Jared Bohem's Flickr stream. It would appear that he has all but two of the codes listed (The Lawn Gnome and Hazmat Guy).
The second list can be found on the website minifigcollector.com. Their list is a full one, with all 16 minifigures listed. Minfig Collector is also an app for Android smart phones, which should be updated with the Series 4 dot codes in a couple of days.
A word of caution - Huw notes that some of the corresponding dot codes don't agree between the two sheets. Given that it's early days, and the dot codes can be difficult to read (relative to the bar codes anyway), it's not surprising. You may also want to try to feel the item through the polybag to make certain you are getting the figure you want. Not sure what to feel for? Head on over to our Series 4 Minifig guides and see what we recommend.