Good tutorial for postfix-gld!

There are a fairly large number of greylisting softwares and they are not very well known so I'm glad to see tips and opinions about them in the comments.

One of the deciding factors for going with Postgrey for me was acually that I did not want any SQL database server. I suppose Sqlgrey with SQLite would have been an option but I like to keep to stuff that is in Debian stable for production use.