Runes were a Germanic method of writing, based upon the Mediterranean alphabets and developed in the centuries after the Birth of Christ.
In this database you can search on over 900 Danish runic inscriptions. Although the database itself is in Danish, there are English translations of the inscriptions.
The National Museum offers runological advice.
The Jelling Project
On the website of the research project, the Jelling Project, which has the monuments at Jelling as its starting point, you can also find information about runes.