But, if you are afraid that the phone may rever to using GPRS/EDGE when you step outside the WiFi zone, just turn off the mobile network while browsing.
I just got back from Spain on Thursday. Where are you headed?
The vast majority of WiFi SSIDs you'll pick-up are WLAN_XX (where XX is a 2-digit hex value).
These are encrypted with WEP by default, they're the routers Telefonica gives to DSL customers.
If you find these routers (made by Zytel, white, single antenna), the encryption key is printed on the bottom of it.
I found various Apple, Belkin, Linksys open connections, and some cities (like Bilbao) have free WiFi zones.
In general, I'd expect to walk a block or two before finding an unsecured access point, even in bigger cities.
