Multiple List Email Script

We're looking for a script to register email addresses to several email service providers at once. Visitors will enter their email address at a Wordpress website similar to this one: [login to view URL] The script will then subscribe the email address to several third party email service providers (ESP) such as A-weber and Get-Response among others. Looking for a script design such that new ESPs may be added or changed by us as needed. We look forward to hearing from you.