With Windows XP all the network protocols are already setup and the IP
address is set for DHCP so if you have a DHCP server all you need to do is
make a folder on your computer shared. This is usually called Shared
Documents and you can make it shared by right clicking on it and selecting
the Properties option. Then select the Sharing tab.
for most of the manual set up stuff, you need to go to the "Folder View" options, and uncheck "Simple File Sharing" this will give you more hands on access to stuff. as for workgroup names and such open up your Network and Dialup connections window and under the Advanced menu there should be an option for Network Identification, this is where you can change most of those settings.