I'm going to have to disagree with the removal of ð from alternative spellings on the ground that it is "the letter and not an alternative spelling of the word". A single letter can always stand for its name (especially as the name words for most letters are not in common use, such as wye for y, except perhaps in derived words such as em dash).
What I mean to say, I suppose, is that when one comes across a standalone ð in a sentence (such as this one) it is read out as "a standalone eth". Given that it has use as a word with the same meaning and pronunciation, I'd consider it an alternative spelling of the word. The same comment stands for thorn, etc. (Which isn't, however, to say that the letter shouldn't perhaps also be in "See also".)—Muke Tever 17:38, 9 Mar 2004 (UTC)