How can I pass values between a Dialog and an Activity?

I am asking the user for input via a Dialog:

package com.android.cancertrials;

import android.app.Dialog;
import android.content.Context;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;

public class CustomDialog extends Dialog  {


    private String name;
//    private ReadyListener readyListener;
     public static EditText etName;
     public String zip;

    public CustomDialog(Context context, String name) {
        super(context);
        this.name = name;
//        this.readyListener = readyListener;
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.mycustomdialog);
        setTitle("Enter the Zip Code ");
        Button buttonOK = (Button) findViewById(R.id.ok);
        buttonOK.setOnClickListener(new OKListener());
        etName = (EditText) findViewById(R.id.EditZip);
    }

    private class OKListener implements android.view.View.OnClickListener {
        @Override
        public void onClick(View v) {
//            readyListener.ready(String.valueOf(etName.getText()));
            CustomDialog.this.dismiss();
        }
    }


}

When the user hits OK, how can I pass the value that was entered in the textbox, back to a member variable in the Activity that launched it?