Gertbysea, surprisingly the best places for free wifi that we have found have been Vietnam and Mongolia! London and Australia are hopeless and depending on where you are in the US it's a bit hit and miss. For convince while travelling around the US I'm going to get a micro sim to use while I'm there this time, a little bit of a fuss but happy for this trip.
I have found that is small towns and villages, especially in fairly remote areas, I get a good WiFi signal when parked near a police or fire station or if they have one, a public library.
The following is copied from Wikipedia on U.S. travel page. Some will not occur to most folks.
By Internet
Most Americans have Internet access, mostly in their homes and offices. Internet cafes, therefore, are not common outside of major metropolitan, tourist and resort areas. However, you do have some options, except perhaps in the most rural of areas.
If you bring your own computer:
Most public libraries have free wi-fi available even without a library card. In some instances, the wi-fi remains on 24/7, so even if the library is closed, you may be able to sit outside and access the internet in the early morning or Sunday.
Chain hotels usually provide in-room Internet connections, sometimes wireless, either included with the price of the room or at an additional charge. Local establishments like bed-and-breakfasts and roadside motels are less likely to have Internet access.
Many coffee shops, bookstores, and some fast food restaurants provide free wireless Internet access, though you may need to make a purchase first. The list includes major national chains like McDonald's, Burger King, Starbucks, and Barnes & Noble.
Some cities have free WiFi access that spans a central business district (several square miles) or even citywide.
Many colleges and universities offer free WiFi in their libraries and student centers, but non-students may have trouble accessing the network, or even the buildings. Ask around.
Airports, even smaller regional ones, usually provide WiFi within passenger terminals, usually for a nominal charge.
There are some paid WiFi chains, where you can receive access to numerous hotspots for a small charge, such as Boingo.
If driving, in a pinch you can always park in a chain hotel parking lot, on a crowded suburban/urban residential street, or by a commercial strip by coffeeshops or libraries, and grab WiFi access from your car. Unlike Europe, most WiFi signals are not password protected and can be easily accessed. Some local municipalities are outlawing this practice, but enforcement is nearly non-existent.
You can also purchase a mobile broadband modem which can be attached to your laptop via a USB drive and subscribe to a prepaid plan. Service providers include Verizon Wireless and Virgin Mobile (Sprint). "
