The online version of the Munich Chronotype Questionnaire (MCTQ), which until recently existed here, is in the process of being moved by its creators to another location on the web.
A useful alternative is the Horne-Ostberg Morning-Eveningness Questionnaire, a version of which you can find here. Completing this online assessment should take about five minutes.
If and when the online MCTQ is back online, we will post it on this page. (You can find the paper version of the instrument here.)