Mal Vikinga - Rapid course in Runic Swedish, available in English and modern Swedish.
Norse Course - Old Norse for Beginners - A course in the Old Norse language for beginners. Includes: Structured lessons, solutions, audio clips, texts with glossaries, rune projects and the ever popular Norse Toons.
Old Norse - Information about the languages of medieval Scandinavia: phonology, grammar, vocabulary list including proper names, texts, and links.
The Old Norse Language - Learn the language of the Viking Age and medieval Scandinavians. Includes basic grammar, phonology, and syntax.
The Old Norse Language Institute - Features English-Norse dictionary, grammar, and texts.
Runic Swedish Grammar - A grammar of the ancestor of Scandinavian languages.
Zoëga's "A Concise Dictionary of Old Icelandic" - Web version of the full 1910 Old Norse-English dictionary, with both .php and .gif files. The grammatical supplement is also included.