[PHP] LDAP and Single Sign On

[Justin Cook]

We are developing an intranet for my company. I would like to implement a 
single sign on service. We have Active Directory on one server and the intranet 
is being housed on a Redhat Linux server. When the internal user pulls up the 
intranet, I would like it to check to see if they successfully joined the 
domain when they logged into their personal machine, if so they do not need to 
log on to the intranet. Does anybody have any links to tutorials on this? 
Thanks!