There are complaints in the Google Web Search Help forums that Google has removed the Google Scholar option from the main drop down navigation menu. This change came with Google's new top bar change from a week or so ago - that is still rolling out slowly.
They have indeed done that, placing it under the "even more" section making it hard for Google's most scholarly searchers to access Google Scholar.
Here is a picture from before:
Here is a picture of the new Google bar:
As you can see, Google Scholar is missing from the new bar.
I honestly think Google will eventually let people customize the Google bar with their favorite services. So that should solve the issue for many. But I am not sure when that will happen.
Forum discussion at Google Web Search Help.