If you search at Google, all the domain names in the AdWords ads should appear lowercase. If not, then maybe you are on an older data center and you will soon see it.
The rollout started Friday afternoon according to a WebmasterWorld thread.
Not all advertisers are happy about it. Especially when using case helps point out the true meaning of the URL. The example given last time still makes a solid point:
PenIsland.com is definitely better than penisland.com.
From >> To
Anyone happy with this change?
Forum discussion at WebmasterWorld.