I am just an amteur student of old english. my main interest is to understand the origins of Dutch, German and English all of which I use on a daily basis. I 1st bought a paper copy of Bosworth-Toller and then I used http://www.utexas.edu/cola/centers/lrc/books/asd/index.html
but this version is much more flexible and easier to use.
Unfortunately, it does not give the translations to related languages. It would be great to compare the words to old Norse, and the above languages. Also a translation back from English to old english would be very interesting.
Anyway, this website is wonderfull !