The openwince project(http://sourceforge.net/projects/openwince) collects free (open source) software tools, modules, applications, drivers, and so on for Windows CE platform developers. Some of the modules are usable outside Windows CE development environment and are platform independent.
Rainer Keuchel has ported many popular Unix tools to WindowsCE(http://www.rainer-keuchel.de/software.html).
The purpose of the SynCE(http://synce.sourceforge.net/synce/) project is to provide a means of communication with a Windows CE device from a computer running Linux, *BSD or other Unices.
PyRapi(http://synce.sourceforge.net/synce/) provides a simple Python interface to the libraries of the SynCE project, which makes it possible to communicate with Windows CE devices. It includes CE_DirView.py, a script that provides access to a PocketPC with PyQt but does not require KDE or GNOME, and a client-server solution for accessing a PocketPC via a remote computer.
MiniStumbler(http://www.stumbler.net/) is a tool for Windows CE that allows you to detect Wireless Local Area Networks (WLANs) using 802.11b, 802.11a and 802.11g.
PocketWarrior(http://pocketwarrior.sourceforge.net/index.html) is a wireless auditing software for PRISM and NDIS 5.1 compatible cards that runs on PocketPC 2002. Binaries for ARM,SH3 and MIPS available Pocket Warrior now supports GPS.
AvantSlash(http://www.fourteenminutes.com/code/avantslash/) allows you to read Slashdot on your Palm or WinCE device (through AvantGo or another PDA Web browser) or via a WAP enabled mobile phones. It provides you with a cleaner version of the content and can even clean up the linked articles for easier reading on your device.
This HOWTO(http://www.cewindows.net/wce/linux-serial.htm) will tell you how to set up a masqueraded PPP connection via IrDA or serial port from a MS-Windows CE PC Companion to a Linux based notebook computer.
Pocket PC System Controller(http://s200.freehostia.com/) is a client-server package that will allow you to use your Pocket PC as a remote controller for your desktop by sending voice commands.