Further information. Every page I find regarding passing data between forms seems to only show passing data from form 1 to form 2. I need to know how to get data from form 2 into form 1.

Ok, the solution is to define your controls in the second form as internal protected to ensure the first form can access them. Then you create an instance of the second form and open it as form2.ShowDialog()
Next you process the second form as you normally would but upon completion, you Close() the second form. You then access the second forms controls as you normally would and hey presto! Done!

one way you can get data back to form 1 without closing form 2 is to define a delegate, and assign that before you show your form 2, then from form2 call that delegate to pass the data back to form1.
public delegate void Foo(string username);
public class Form2 : Form {
public event Foo Foo1;
public Foo Foo2;
// this is the same for both
void OnFoo1(string uname) {
if(Foo1 != null) Foo1(uname);
}
// where ever you need to send the username back
void Validate() {
// if data is valid
OnFoo(textBox1.Text);
}
}
Form2 code:
Form2 f2 = new Form2();
// depending on if you want it as an event...
// not that it reall matters here
f2.Foo1 += new Foo(FooMethod);
f2.Foo2 = new Foo(FooMethod);
f2.ShowDialog(this);
// FooMethodImplementation for the event
// or delegate from Form2
void FooMethod(string username) {
// or whatever you do w/ this info
this.textBox1.Text = username;
}

Cheers MH! That is very useful right now. :-)