1.The AD plugin is built in to OS X 10.5. If you go to the Directory Access program which is in Applications/Utilities you will see a list of configurable directory services. Click on Active Directory and then Configure. You will need to know your AD forest and domain name, give your mac a computer ID and then click on Bind. It will then ask you for the credentials of an account with permissions to join a computer to the domain (ie a domain admin) and that should be all.
If it fails to bind to the domain it is usually because your AD is not configured correctly.
http://images.apple.com/itpro/pdf/AD_Best_Practices_2.0.pdfhttp://macwindows.com/leopardAD.htmlhttp://macwindows.com/AD.htmlSource :
http://www.experts-exchange.com/Apple/Hardware/Apple_Laptop/Q_23837170.html
