Do I use "..." or brackets?

Question

When omitting a portion of a quote, do I use "..." or brackets?

Links to relevant passages in on-line style guides would be most welcome. :)

Answer 1

(Exact Quote)"Music has come a long way since […] But it will never supplant the sounds of traditional instruments" (Taylor 37).
via http://www.loyola.edu/library/REF/MLA.HTM

To quote 4 or less lines of prose, you can include the passage within quotation marks as part of your text, e.g. Dick Oliver concludes that "all communication industries [. . .] are moving rapidly toward exclusively digital technology" (24).

To omit part of a quoted passage, you need to indicate the omission by the use of 3 spaced dots enclosed in square brackets, e.g., "The local politicians believe welfare [. . .] should all be paid for through income taxes" (Stewart 1).

via http://www.aresearchguide.com/5quoting.html