These are the steps that I’ve followed to connect the chumby one through 3G using the Huawei E169 datacard.

a) Installed Ubuntu 10.10 on VMWare and created this txt file :

<configuration apn="naviga.tre.it" username="" password="" number="*99#"/>

b) Copied the previous file to the USB stick with the name "3g_config"
c) Attached the USB keyboard and the USB stick to the chumby one through the USB splitter
d) mounted the USB stick
e) Copied the 3g_config file to the folder /psp/ on the chumby one
f) turned off the chumby one and removed the USB keyboard and the USB Stick
g) Attached the Huawei E169 3G data card to the USB port and turned on the chumby one
h) Gone to the Network Config screen and pressed the top button, gone to Settings, then tapped on Network.
i) Selected "create a new connection", pressed OK, and waited for the scan to time out.
l) Selected "Other"
m) Entered 3G as the name of the access point.
n) Waited for the subsequent scan to time out.
o) Selected "Manual".
p) Tapped "OK" to select None as the encryption type.
q) Tapped "OK" to select Automatic IP allocation.
r) Tapped "OK" to confirm settings.

The connection hasn't been established,because this error :

ppp0 device not found
ppp0 interface is down
ppp0 link is down
failed to obtain IP address
chumby.com is unreachable