getting all the machine names in the network

hi frndz..
I have a form --> contains a textbox, a dropdown menu ( and some other controls )
I also have a code such that if we give any IP address in the textbox, the (specific) servers running on that machine ( of the IP Address we provided) will be displayed in the dropdown menu.
Now, I have to add a button ( to browse) such that on clicking the button, all the machine/server names in the whole network will be displayed in the dropdown menu
What are the suggestions/help you can give??

Thx

Would that be an Active Directory setup?

This rather easy sample contains a module which can be found multiple times in the web. Took me a while to dig it out.
Can't really say, where I had it from. There are multiple origins, all slightly different, but basically the same code.
It lists all domains and all computers of a selected domain. Also works with workgroups. The essential code is in the module. The form is just for demonstration how it works.