I am not sure that this is the right place for this question so if not please advice me where to ask.

I am currently building a HTML e-mail template with sophisticated design and I am wondering how & where to test it. In "how & where" I mean which are the most common mail applications for desktop and mobile devices. So is there some emulators of mobile devices where I can test how it looks. For web I am going to test Gmail and Yahoo - do I have to test something else?

Any ideas will be appreciated.