you need to get the ip address, user name and password to enter into the system.
To find out the ip address, you can start the terminal in iPAQ (GPE installed), and type ifconfig.
Copy files forth and back with scp on Linux Host:
scp foo email@example.com:/home/root
scp -p -r firstname.lastname@example.org:/home/root/foo foo
Right now my iPAQ's ip address is connected to the wireless network, and is associated with an external ip address (NOT 192*), so it can not ping my internel network, but the linux host can ping the external ip address. That is why scp works.