Haven't posted here before, but I've been learning Colemak since late August last year (2011). Coming from standard QWERTY, I was pretty confused while 'unlearning' QWERTY at first, but it gradually settled down.
I started off practicing with the KTouch program for linux, easy program to practice with. I think I did about half an hour to start with, daily... but I lost count and didn't do it consistent enough I suppose.
In September I changed my Android phone keyboard layout to Colemak perminently (using MultiLing keyboard, and now SwiftKey X), to kinda get used to it at least. I think that helped somehow looking at the keyboard and typing.
I switched back and forth from QWERTY on the computer (using linux OS's) for the first 2 months before I fully switched the computer and laptop to Colemak. Of course I was really slow at first and making lots of mistakes, but I feel like I'm back up to speed now... and it feels good! Speed is still increasing bit by bit, and I'm still trying to get used to the backspace key @ the CAPS Lock spot. Making a little more use of it these days, but also still use the normal one, heh.
I played typeracer for a couple of times while I was still on QWERTY, so this makes it at least somehow a little more comparable, but notice I left out most of the tests because of only practicing on KTouch, and it doesn't really show any progress afaik. And Typeracer doesn't show if you type too slow (you have to finish within a certain time).
QWERTY speed last year (August): 71 WPM
Colemak after 5 months (January): 50 WPM
Colemak after 6 months (February): 55 WPM
Colemak after 7 months (March): 57 WPM
Colemak after 8 months (April): 60 WPM
Colemak after 9 months (May): 63 WPM
As you can see I'm still getting back up to speed, but there are some races in which I score above 70 WPM again. Woohoo! :)