I have a simple squeeze page setup for a client, to which I drive PPC traffic from Adwords.

Link to my Squeeze page

My autoresponder is Mailchimp and I used their embed code for the customized form, but I haven't found an easy, simple way to set up tracking the opt-ins so I can tell what keyword was used for each opt-in.

With Aweber, it is straight forward, you add a line of code to redirect to a custom thank you page on which you place your Google script, but Mailchimp creates and hosts the forms and thank you pages for you - you can create your own, but you have then to edit the opt-in form to insert a redirect, and I don't know what embed code to use for the form.
This last part is what I don't know how to do.

Anybody to help me out who has worked through this (with Mailchimp) before?

thanks

PS: Aweber is bad at supporting french accent/characters, hence I moved my french clients to mailchimp