Currently, the options are: GetResponse, AWeber, SendReach, SendLane, MarketHero, and ImnicaMail.
As an affiliate, you are only able to use GetResponse and SendLane through the JVZoo system.
Sellers have other options, because they are doing the programming for their own sites, but affiliates are limited at this time.
You can also create your own integration, by using the IPN forwarding section to integrate:
Read an article on writing your own script here.
You can also include a squeeze page within the delivery system and have your customers manually enter their email. Currently these are the only ways to use a non-supported autoresponder.