The preferable format for importing into the database, if the item is not written directly in the web interface, is BibTex. If you are not familiar with this format, you could read the information from the official site or you could read the page in Wikipedia. In both cases please follow the links and the information provided there.
A good editor for bibliographic items in this format is JabRef, which is available for various ranges of operating sytems. However, you could use whatever editor you like which supports this format.