Maybe it's me but i haven't been able to successfully find a WIFI spot, with my first generation and non-3G iPhone, if I'm not connected somehow to the internet (WIFI...).
There are some apps out there, if you do a search in the app-store on "wifi" or "spot", maybe they work well if you walk around with your iPhone in a WIFI hotspot dense area.
In my usual habitat it's not a problem, becaue i know my usual suspects, but now I'm in Amsterdam, where the weather is grey and typical water-cold, i don't want to show of my mobile device too obviously for security reasons. And I'm not staying in a fine Le Quartier Hotel with free WIFI. I feel lost, i got lost and i need to download a map, maybe check out the website of public transport to see what tram to take and so on, all the things a healthy mobile and internet addicted person needs.
Well the easier way could be the check out this website with the worldwide WIFI spot finder : www.free-hotspot.com (Before you go on your trip )
Find the nearest hotspot and voila you take it from there!
And for the gadget-lovers they have also a iPhone app and a Skype tool.