Ajax Register PreSales Questions

A couple of questions:
1. Regarding custom fields, can you set a default value?  i.e. checkbox = checked?
2. Can you send admin emails only when certain custom fields are checked yes?  i.e. custom field "Would you like us to contact you?" = yes, send admin email, if = no, do not send admin email.
3. Does your registration form work with plugins like acymailing where we can display a custom field like "Subscribe to our newsletter?"
Thanks!

1. Yes. See www.sakic.net/content/scripting_files/aj...ter/adding-field.gif

2. No. Up to yourself to handle the user input.

3. No. Maybe in future.