While I'm not new to developing websites, I've never had the opportunity to use iframes ... until now. In addition, I believe I'll be using iframes in conjunction with a web service, but not positive.
So basically: what are iframes and how does one use them (i.e. what are the most common applications of iframes)?
I know what I've seen of the code for them, but I would like to get some feedback from someone who has used them extensively to get a better sense of how they work and how to implement them. URLs to a solid web tutorial on the subject are also welcome :)