Occasionally I've noticed that, while most fics are spell-checked, spelling
errors still creep in where one word is mistyped, and becomes (either through
misfortune, or misapplication of an overzealous program) a different
(correctly spelled) word.

  When offering criticism, should these be referred to as spelling errors?

	I've heard these referred to as "word-o's" (to distinguish them 
from "type-o's").  Since the problem stems from a severe misspelling of 
the original word, they are spelling errors.

  Does anyone have any advice on the best way to prevent this from happening
in my own stories?

	1) Re-read everything you write before you post (quality control 
is one of the reasons why all my chapters are so short).  2) Develop a 
strong vocabulary so that you catch your own mistakes.  3) Learn the 
meaning of the words/phrases you're writing.  I cringe whenever I see 
authors blindly parroting what they think the characters say ("Hoist by 
my own Picard," indeed).
 

  What is a convenient method for reporting these back to the author?

	The same way you'd report any other spelling/grammar mistake.
	Hope this helps.
 ______
{B-{=__
rmckenzi@euclid.ucsd.edu : The White-Robed Mathematician