Cross user control communication via parent control.

[zb]

Here is the page architecture:
Page loads multiple user controls (including nested user controls)
dynamically based on parameters provided into place holders. Note: The
page only has the logic to load the user controls and subscribe to
custom event exposed in the user controls.

Scenario:
User comes to this page fills the fields generated by multiple user
controls and then hits "Save" button in one of the forms.

Question:
- How can all the information be collected in the control that has the
save button and saved to a repository?
- Is there a better practise?
- How can all the user controls be "wired" together to cross
communicate?

An example will be great help.

- Working with ASP.Net 2.0 using C#

Thanks in advance.