Delegating Control of an Organizational Unit in Windows server 2008

How can I increase the number of PCs a specific user can join to a domain?

1. Open the ADSI Edit MMC snap-in and connect to the Domain Naming Context.
2. Right-click on the domainDNS object for the domain you want to change and select Properties.
3. Edit the ms-DS-MachineAccountQuota attribute and enter the new quota value.
4. Click OK twice.