Sound the trumpets!!!! Probably I have been entirely out of the loop and everybody else knows of this already, but regardless I have found what may quite possibly be one of the greatest online tools for students of Old English – besides the online Bosworth-Toller Anglo-Saxon Dictionary, of course (and I see that the online version is improved over the downloadable freeware version which I have).
Here it is: an Old English <=> Modern English online translator which even gives complete paradigms of the Old English words!!! What is particularly great about this tool is if you come across a word in Old English whose root you cannot recognize, you simply enter the form you have in front of you and the tool will match it up to the correct root via the paradigms. For example, if you enter “drunce” you get the full paradigm of the verb “drincan” with the 2nd sg. active preterite and singular subjunctive preterite forms in red text, as “drunce” corresponds to both those forms. Awesome!
On a final note, one other resource that is quite useful is the Thesaurus of Old English, which acts as any other thesaurus by giving you words in Old English that are related to the original concept you search. A great feature of this thesaurus is the ability to search for entire phrases, something which is difficult to do in dictionaries.