CheckPoint has an IPSEC VPN client for WinCE 3.0 that might be worth looking into. There are others who offer them as well. From the Microsoft white paper on PDA security: "Data can even be encrypted (e.g., with triple DES technology) when using the Internet to connect to a corporate server using a virtual private networking product such as the one from V-ONE Corp.. V-ONE supports two-way authentication when making the connection over the Internet. Additional VPN solutions are available from Certicom Corp., Epiphan Consulting Inc., RemotePipes Inc., and WRQ Inc." You can find that white paper at http://www.microsoft.com/mobile/enterprise/papers/why.asp.
Microsoft has been talking about adding one natively into the WinCE OS or in the ROMs for quite some time but I haven't heard much about it since last year's Go Mobile Conference. Good luck.
J.R.
