OK, messages are translatable.
For forms, I have to create a different form for each language.
Hi there. I do have wpml and I like mailchimp. Did you make it work? I have three languages and would like to link each language to a different list. Thanks for letting me know.
You have to create multiple forms (feature available only in version PRO).
Hi Guido,
Most people do indeed use the Pro version for this as it gives you the option to create multiple forms. You can then create a form with translated messages for each language and show the form based on the currently viewed language.
To show a different form widget for each language, you can use the tips outlined in this article: http://wpml.org/2011/03/howto-display-different-widgets-per-language/
I am currently working with the WPML people for improved compatibility so there are a few updates on this on its way. Since the sign-up forms accept raw HTML it is not likely that these will be fully translatable in the free version though, it’s technically a little hard to do.
Hope that clarifies!