Removal of pages from index

How can I have my web site or web pages removed from the search engine?

[EarWig]

Yahoo Help says at [help.yahoo.com...]

"There are several ways to prevent our crawler from indexing your site or portions of your site:
create a "robots.txt" file on your web site to prevent our crawler from indexing your site
add a "noindex" meta tag to your documents"

I completed all these on a site many months ago and it is still listed - just the full URL - [widgets.co...] uk no snippet or cached version.

Any thoughts/help?
EW