I am not sure that I can help you directly. Maybe one of the other members can.
When using VPN you need two different ends. On one end a client must be installed
(e.g. Movian, VPN-1, SmartPass...
) on the other end - usually central location - a Gateway or VPN server is needed. There are
(at least
) two types of VPNs. First group is based on standard protocols
(Movian - IPSec, I think that VPN-1 is the same type
) where a standard Gateway , e.g. Cisco router can be used on central location. The other type is proprietary solutions. In such case you need the server and the client both from the same vendor. There's an interesting article about handheld VPNs:
http://www.pocketpccity.com/articles/2004/12/2004-12-6-Handheld-Security-Part.html
I was in contact with NetMotion
(from their web pages I could conclude that a standard protocol is supported
) who told me that they have a proprietary solution - don't waste your time on them unless you have a business case. They are willing to give you a trial for both: client and server side.
I am not aware of any open source or free VPN Gateway. There is one, in fact, but no PDA clients
(yet
). A challenge for you to do the portation
?
Maybe cou can find a small router on the market that has built-in VPN Gateway capabilities. I don't know such a product but maybe other members do. This could be a solution for you. I am sorry that i can not give you a better answer.