Help with integrating Ubuntu into a windows domain

[AsherSevyn]

So I have the task of integrating our businesses first Linux server into the network.
My success or failure in this project will determine whether we use more linux in the future or scrap linux and continue using microsoft products.

This Server is running Ubuntu 9.01 loaded with Samba and Likewise-Open.

This server must be able to join the domain for the shares to be established.

Your mission, should you chose to accept is to help me establish a samba shared folder on the network available to all Microsoft users.

I joined the domain successfully according to the server however I cannot see the Ubuntu machine on the network. I can ping it but something is wrong.

Where should I start looking to find out what is broken?