Cameron, Angus et al. Dictionary of Old English. Toronto: Pontifical Institute of Medieval Studies, 1986- . This dictionary will supersede Bosworth-Toller (previous item). It is printed on microfiche; letters a-e are now available.
* Clark Hall, John R. A Concise Anglo-Saxon Dictionary. 4th ed. with supplement by Herbert D. Meritt. Cambridge: Cambridge UP, 1970. Recently reprinted by the U of Toronto P in the series Medieval Academy Reprints for Teaching. The best dictionary for students. There's often a copy or two in the U.Va. Bookstore.
Bessinger, Jess. B. A Concordance to the Anglo-Saxon Poetic Records. Ithaca, NY: Cornell UP.
Healey, Antonette diPaolo and R.L. Venezky. A Microfiche Concordance to Old English. Toronto: U of Toronto P, 1980. A concordance to the entire corpus of Old English (poetry, prose and Old English glosses to Latin texts). Excludes only the most common "grammar" words.