Launch default browser and post data to the web

Question

Hi !

I read about host a web browser in C# window application using Microsoft Web Browser (http://support.microsoft.com/kb/313068).
Is it possible to use Microsoft Web Browser COM components in a pc that doesn't have Internet Explorer installed on it?
For instance, the user only has firefox or Safari installed on his or her machine.
And, can Microsoft Web Browser COM component works in IMac?
Can I just include the dll on my setup file ?
If not, Is it possible to use System.Diagnostics.Process.Start or System.Windows.Forms.WebBrowser ?
Is it possible to post data using System.Diagnostics.Process.Start or System.Windows.Forms.WebBrowser?
Thanks