Different between XP Home and XP Prof
XP Home User management, Limited to 2 security levels, no policies
vs
Full User Management and Security Policies
XP Home Limited to Workgroup network (unable to join a domain)
Xp Home has no security on sharing disks and folders, everybody has access to shared data
XP Home max 5 simultaneous file-sharing connections
vs
XP Pro 10 connections
XP Home has limited disks and folders security, made difficult to use. XP Pro has full disk/folder security based on User Management (and also Encrypting File System with NTFS file system).
XP Pro has Remote Desktop Access, Backup Program, ASR Automatic System Recovery but not XP Home.
The lack of the possibility to join a domain and the lack of securing a shared network resource will prevent the use of the XP Home edition in most office networks, even in configurations where Windows95/98/ME could be used.
Microsoft also has a page to describe the different between the 5 different versions of Windows
http://www.microsoft.com/windowsxp/evaluation/compare.mspx
XP comparison guide
http://www.microsoft.com/windowsxp/pro/howtobuy/choosing2.mspx