Thought I'd start listing cafés and other places with wireless access points as I come across them. Maybe my googling skills aren't that great but I couldn't really find a list like this anywhere. Anyway, here's number One...
Alphabyte Café in the Shepherd's Bush Shopping Center, W12 London. It's a coffeeshop, newstand, internet café with four screens, and mobile phone store with free wireless access. Not particularly luxurious but functional and not too crowded. And free access.
Torrefazione at 1234 Government Street, Victoria, B.C., Canada. Found it through FatPort. It's a commercial service though. $4.95 CDN for an hour (unused time cached for 90 days). $6.95 for 4 hours (but expires immediately afterwards). $9.95 for 24 hours (but again immediately expires 24 hours later). etc.
NodeDB.com Not a physical site just a link to a wireless node database listing open nodes around the world. Have to check out Benugo's Sandwich shop in Clerkenwell.
BT phone boxes BT now has a number of phone boxes that are wireless nodes near motorway service stations, airports, conference centres, hotels and cafes around the country. Pricing is £6/hour or £15 for 24 hours, plus various other schemes you can see at http://www.btopenzone.com/Openzone/buying.jsp
Also City Airport has a wireless network which you pay for, not sure how much as I didn't have time to do so.
also try http://www.intel.com/unwire for a pretty good list of wireless hotspots