If you want change server name at Netbeans 6.8,

First close your IDE

go to C:\Documents and Settings\kullanici-adi\.netbeans\6.8\Config\J2ee\InstalledServers
folder

And open this file (.nbattrs) with a simple word processor like notepad.

This is a kind of xml file. Find block of server you want change. And change displayName
value.