Windows XP comes in Professional and Home versions. Servers will also come out, but they are still in beta testing.
The features of Windows XP Home and Pro are very similar. Most home users have no need to the Professional version. Windows XP Pro has support for multiple processors and an encrypted file system.
Windows XP has many new features. Users upgrading from the 9x code will find the larges changes in terms of stability. Other great advances are built-in CD-R/RW support, Remote Assistance, a built-in firewall, and Device Driver Rollback.
Here’s exactly what Microsoft says:
PC with 300 megahertz (MHz) or higher processor clock speed recommended; 233-MHz minimum required;* Intel Pentium/Celeron family, AMD K6/Athlon/Duron family, or compatible processor recommended
128 megabytes (MB) of RAM or higher recommended (64 MB minimum supported; may limit performance and some features)
1.5 gigabyte (GB) of available hard disk space.*
Super VGA (800 × 600) or higher resolution video adapter and monitor
CD-ROM or DVD drive
Keyboard and Microsoft Mouse or compatible pointing device
You can check out more information on Windows XP requirements here for Home or here for Pro.
Windows XP Home is $99 for an upgrade copy and $199 for the full version. Windows XP Pro is $199 for the upgrade version and $299 for a full copy.