VisitDenmark is the official Danish tourist portal. The portal is filled with valuble tourist information. Here you can read about some of the main attractions of Denmark as a tourist destination. You can also get information about transportation and accomodation.
It is a recommendable read for anyone planning to travel to Denmark.
VisitCopenhagen is a very useful portal as well if you are visiting the capital city, Copenhagen. Here you can read about the attractions of Copenhagen as a tourist detination and get informations about practical things as booking hotels, shopping oppurtinities, eat and drink etc.