I was just reading a post saying that outgoing links to "bad neighborhood" sites can be extremely harmful to your serps. I have heard that before but how can you find out if a link you are considering putiing on your site is considered "bad neighborhood?"
See if site has mature sites listed or linked to it. You could search site in yahoo and see links that link to site first
also, make sure the link you are adding on your site is related to the same content of your own site. you can do some reading on this article http://www.webconfs.com/bad-neighborhood-article-13.php
Porn, gambling, spam, warez, etc. are all bad sites to have outgoing links to. It doesn't affect your rankings negatively, however, if they link to you (if it did competitors would get your links for you ). Also, be careful about linking to sites with no/gray PR.
You can try this tool out, see if it helps diagnose who you want to link to: http://www.bad-neighborhood.com/text-link-tool.htm -Michael