In order to access shared files on a Windows XP computer (or any computer running Samba) from a Mac, the Mac will need to "connect" to the Windows XP computer and "mount" the shared files.

Please note: Images show in the Mac guides may vary slightly to what you see on your screen. This is due to minor changes between different versions of Mac OSX.

Instructions:

Start at the "Go" drop down menu at the top of your screen, then "Connect to server".
If the computer you wish to connect to is listed, just select it from the list.
If the computer is not listed, type into the "Server Address" field 'smb://' followed by the computer name or IP address of the computer to which you want to connect.
Click the "Connect" button in the bottom right corner of the window.
 

Enter in a username and password. If you want the Mac to remember your user name and password combination, check the box "Add to Keychain".
The workgroup name needs to be the workgroup the PC belongs to. If you don't know the workgroup that the PC belongs to you can find out by right clicking on the "My Computer" desktop icon on the PC, selecting "Properties" and then selecting the "Computer Name" tab. The workgroup name is about half way down the window.
Click the "OK" button in the bottom right hand corner of the window to finish.
 

Select the "share" you are after. This simply refers to a particular group of shared files. Click "OK".

If successful, the shared files will now appear in a window and an icon link to this share will appear on the desktop
 

If the Mac has both "Windows file sharing" and "Allow user to log in from Windows" enabled (the guide File sharing between Mac and PC shows you how to do this) you can access the Mac in the exact same way you connect to a PC from Windows XP: from My Network Places.

Instructions:

On Windows XP: Double click the "My Network Places" icon on the desktop. \

In the "My Network Places" window, double click "Entire Network".

In the "Entire Network" window, double click "Microsoft Windows Network".
 
Double click the Workgroup to which the Mac belongs.
 
The Mac should appear in the listed computers. Double click the icon to show the Mac's shared files.