Not every coffee shop is friendly to laptop toters these days. Then again, some are absolutely great to set up inside. LaptopFriendlyCafes.com lists more than 300 places around the globe that have plugs, Wi-Fi, 3G, and, oh yes, coffee.
The specs that the database site has on each cafe is pretty impressive — confirmed tests of 3G coverage (though no carrier in particular is mentioned), free or low-cost Wi-Fi, and directions and official website links, when available. There aren't a lot of consumer reviews at the moment, and the coverage is mainly in bigger cities. Still, if I was lugging my laptop up to Toronto, I'd hit this site before venturing out.
The site is free to use, allows for cafe submissions, and offers an iPhone app version that, honestly, only covers New York, London, Sydney and Melbourne — though, if you live in those cities, it will get you to laptop-friendly spots with turn-by-turn directions.