Denmark is 1 hour ahead of GMT/Universal time.

In addition to that, Denmark has summertime from the last Sunday in March to the last Sunday in October. This means putting the clocks one hour forward in March and one hour back in October:

2009: from 29th of March to 25th of October
2010: from 28th of March to 31st of October
2011: from 27th of March to 30th of October