SysProt AntiRootkit is a free tool to detect and remove rootkits. Currently, SysProt AntiRootkit supports Windows 2000/XP/2003 32-bit operating systems. Some of the key features of the tool are:

Hidden process detection and removal
Hidden driver detection and removal
SSDT hooks detection and removal
Kernel inline hooks detection and removal
Sysenter hook detection
TCP/UDP ports information
Hidden/locked files detection and removal
Recent Changes:

SysProt AntiRootkit v1.0.0.8:
Improved hidden drivers scanning. Now, SysProt AntiRootkit can detect and remove Zlob (Alureon or TDSServ family) rootkits successfully
Modifications in hidden files scanning. Users can now choose between full system scan or only root-drive scan
Improvements in service/driver disabling mechanisms