VNC & Remote Desktop
VNC allows you to remotely access a computer. It provides a user with a graphical interface to connect to another computer over a network connection. The user employs RDP client software for this purpose, while the other computer must run RDP server software.
Microsoft Remote Desktop
With the Microsoft Remote Desktop app, you can connect to a remote PC and your work resources from almost anywhere.
Windows Professional and Windows Server editions are supported. To view the full list of supported Windows versions and successfully connect to a Windows PC, read the FAQ at http://technet.microsoft.com/en-us/library/dn473007.aspx
Parallels 2X RDP
Seamless and secure remote desktop access. Supports standard RDP and Parallels 2X Remote Application Server connections.
The downside is that connections will only be secure (encrypted) if you applied a paid-for license to VNC 5 (or took a trial).