The PDA's will work the same way everywhere.
You could connect to a wifi network using a PDA to get internet access. You should be able to find some places that give free access.
You could also connect to your phone using bluetooth and use that to connect although your network will charge for roaming data access.
Buy Fujitsu Siemens Pocket LOOX N560
This would cover what your looking for.
You could also go for a PDA/phone.
Buy HP iPAQ Data Messenger
This has a touch screen and slide out keyboard.
You can add satnav software to both of these and the maps would be on a memory card.