Another way to do this:
Open Finder, Applications: Utilities: Directory Access.
In this App: Services Tab:
check Enable Active Directory, then click the configure button
Enter the name of your AD Forest and Domain and give the computer a unique ID, then, click the carrat next to Show Advanced Options.
Check Cache last user.., Next to Prefer this domain, put the name of your domani controller (include the .company.com), then mark the Allow Administration by and add the users you want to have Admin on this computer.
Click Bind. Hopefully you are a Domain Administrator in your AD environment, or are friendly with one. This will create the account on the Active Directy for your Macintosh.
But wait there's more:
CLick the Authentication Tab, change the Search to Custom Path, then click the Add Button and select /Active Directory/domain.com. Then click the Contacts Tab, change Search to Custom Path then click the Add button and add /Active Directory/domain.com
Then click Apply.
Now ANYONE on your domain can log into the macintosh but clicking Other if you have users listed, or simply entering their user@domain.com ID and their password. They can also create a cached account so if they are "offline" they can still log in.