From its website:

I have compiled the VNC client for the PocketPC by adapting the WinCE 2.x 
source. This is my first attempt to make the user interface PocketPC friendly, 
so it may still have some issues. This download is completely free, and is
available in ARM/Xscale, MIPS, and SH3 binaries. Please note this ONLY works 
on PocketPC devices. To install, copy the correct vncview.exe for your cpu 
type to the device. To uninstall, delete the vncview.exe on the device. 
Note: The Intel Xscale PXA250 (ARM) processor is supported. 

You can get it here: http://www.cs.utah.edu/~midgley/wince/vnc.html