Your Smaba config contains all that data, you can edit it manually using a text editor it is located somewhere in the /etc directory and the file will be named smb.conf or you can use something like swat, or webmin, or in KDE control panels. It is pretty easy the setting is named workgroup, if I recall correctly. The defuault workgroup name for XP home is "MSHOME" the default for XPPro is "Workgroup" but they may be different if you set it up that way. YOu will need to restart samba following the change and give it time to propogate throughout the network after samba forces an election for workgroup browse master. The propogation can take up to 24 hours if I recall correctly.