I am an avid user of Litmus for spam testing. It is a very cool online service that basically sends your email on a dry run up against a comprehensive list of spam filters.
I know some people (you know who you are) for whom a Litmus spam test is their personal nemesis. But for me it becomes like a game of chess. Anyway, if you don't already use it, go check it out (and no I'm not on commission).
On their blog, they've got a webinar by Tamara Gielen, an email marketing expert based in Belgium. Tamara gives a great overview of many of the considerations you need to think about in creating successful email campaigns.
The webinar is embedded below. The original post also has a bunch of useful links.