Googler, JohnMu, has some basic linking advice in a Google Groups thread. In short, John explains that logic behind who you should or should not link to. I’ll quote John:

Did we learn anything new from this? Not most of you, but for our new readers or those searching for “advice on linking out,” this article may come in handy.

If you have more questions, join the thread at Google Groups.

Note: This article was written last week and scheduled to be published automatically on Monday, April 21st.