MultiVNC is a cross platform multicast enabled portable VNC viewer. It can be used for stand alone VNC (Virtual Network Computing) to remotely connect to VNC Servers allowing you to access and share remote desktops on platforms that are running Windows, Linux, Unix, or Mac OS X.
UltraVNC Viewer is an open source portable VNC viewer that provides secure remote desktop access without requiring installation. This Portable VNC Viewer allows users to connect to and control remote computers using their local mouse and keyboard. Designed for flexibility and portability, Ultra VNC is ideal for IT support, system administration, and remote troubleshooting directly from a USB flash drive.
RealVNC offers a free edition of its popular VNC viewer client software that can be stored and launched from a USB device. Virtual Network Computing (VNC) enables users to remotely view and control computers running a compatible VNC server. This stand alone remote desktop client provides encrypted access to remote machines from virtually anywhere, making it a convenient solution for personal remote access and on the go support.