I came across a very helpful site that has a list of Free Wi-Fi spots in the U.S.. The site is at WifiFreeSpot.com and since I live in Chicago, here are all the listed Free Wi-Fi spots around town:
 
Chicago Alliance Bakery & Cafe - 1736 W Division St - (773) 278-0366 Apple Store - signal carries outside of store - 679 North Michigan Ave. - 312-981-4104 Argo Tea Cafe - 958 W Armitage Ave Argo Tea - 819 N Rush St - (312) 951-5302 Argo Tea - 16 W Randolph St - (312) 553-1551 Art Gallery Cafe - 1907 N. Milwaukee Ave - 773-235-2351 Atlas Cafe International Kitchen - 3028 W. Armitage - 773-227-0022 Atomix - 1957 W Chicago Ave - 312-666-2649 Bluepoint Oyster Bar - 741 N. Randolph Bluepoint Lounge - 123 North Halsted Bobtail Soda Fountain - 2951 N. Broadway - 773.880.7372 Bridgeport Coffee House - 3101 S. Morgan Bronzeville Coffee House - 528 E 43rd St - 773.536.0494 Buena Park Social Club - 4181 N Clarendon Cafe A'riana - 1826 West Wilson Avenue - (773) 271-3940 Cafe Ballou - 939 N. Western Ave. - 773-342-2909 Cafe Latakia - 3204 N. Broadway Cafe Mestizo - Tianguis Books - 1646 W. 18th St. - 312.421.5940 Cal's Bar - 400 S. Wells Street Camille's Sidewalk Cafe - 400 N. LaSalle Street - 312-329-9727 Caribou Coffee - 2453 N Clark St, W. Arlington Place - 773-327-9923 Carmichael's Chicago Steak House - 1052 W Monroe Ave - 312-433-0025 Catedral Cafe - The Coffee Shop of Will Ferrell - 2500 S. Christiana Ave - 773-277-CAFE (2233) Charmers Cafe – 7406 N. Greenview Ave Chase Cafe - 7301 N. Sheridan Rd Chicago Public Library - 400 S State St and all 79 branches Clybar - 2417 N Clybourne Ave - 773-388-1877 Coffee on Milwaukee - free w/purchase - 1046 N. Milwaukee Ave. - (773) 276-3200 Corona’s Café - on Irving Park near Sheridan Ave Daley Plaza - between Clark and Dearborn Delicatezza - 186 N. Wells - 312-456-0901 Diana's Nail & Spa - 175 N Franklin - 312-332-2662 Dog Day Afternoon - 7183 W. Armitage - 773-745-7557 Dollop Coffee - 4181 N Clarendon - 773-755-1955 Dunkin Donuts - 5615 S Harlem - 773-586-6460 Fado Irish Pub - 100 W Grand Ave - 312-836-0066 First Bytes Computer Center - 2nd Floor, Berger Park, CPD - building and campus grounds - 6205 N Sheridan Rd - 773-761-5792 Fixx Coffee Bar - with purchase - 3053 N. Sheffield Ave. - (773) 248-0841 Goose Island Brewpub - 1800 North Clybourn Ave. - (312)-915-0071 Grind House Coffee - 307 S. Halsted - 312-382-9464 Heart Boys Cafe - 3404 N Halsted - 773-244-9866 Homan Square Community Campus - 3517 W Arthington Ave Illinois Institute of Technology Intelligentsia Coffee & Tea - 55 East Randolph Street Ipsento - 2035 N. Western Avenue - 773.384.1870 Istria Cafe - 1520 E 57th St - 773-955-2556 Jack's Java - 9649 S. Western Ave - 773-239-5282 Kristoffer's Cafe & Bakery - 1733 South Halsted - 312-829-4150 Lemmings - 1850 N Damen Ave - 773 862-1688 Little Branch Cafe - 1251 S Prairie Ave - 312 360 0202 Marrakech ExpressO - 4747 N. Damen Ave - (773) 271-4541 Marshall Mcgearty Tobacco Lounge - ask for password - 1553 N Milwaukee Ave Mercury Cafe - 1505 W Chicago Ave - 312-455-9924 Metropolis Coffee Company - 1039 W. Granville Ave. - 773-764-0400 Millenium Park - north and south ends - Michigan Avenue between Randolph and Monroe Streets Mo Joe’s Hot House - 2849 W. Belmont Ave. MoJoe's Cafe Lounge - 2256 W. Roscoe - 773.388.1236 Mother Hubbard's Sports Bar - 5 W. Hubbard St. - 312-644-7711 Muse Cafe - 817 N Milwaukee Ave. - 312-850-CAFE Ndiga Coffee & Books - 3510 west 63rd Street - 773-925-2517 Panera Bread - 616 West Diversey Panera Bread - 2070 North Clybourn - (773) 325-9035 Pause Cafe - 1107 W Berwyn Ave - (773) 334-3686 Piece Brewpub - 1927 West North Avenue - (773) 772-4422 Pressure Billiards & Cafe - 6318 N Clark St - 773-743-7665 Quenchers Saloon - 2401 N. Western Avenue - 773/276-9730 Quiznos - 8303 S Stony Island - 773-221-2098 Reggies Music Joint - 2105 S State St - 312-949-0120 Rick's Munchies Cafe - 3511 South King Drive - 773-536-3500 Ritz Coffee House - 933 N Ashland - 773-235-3100 Royal Cafe - 1507 Foster Ave. - (773) 907-0727 Savor the Flavor - 2545 N. Sheffield Ave. - (773) 883-5287 Siam Rice Thai Cuisine - 117 N Wells St - 312-606-9999 Sidekicks - 4424 W Montrose Ave - 773-545-6212 Silvie's Triple D Pub - 1902 W Irving Park - 773-871-6239 Sip Coffeehouse - 1223 West Grand Avenue Soul Cafe Coffeeshop - 1301 West Hollywood - 773-517-6501 Staples - 111 North Wabash Ave - 312-641-1213 and 4610 North Clark Chicago - 773-769-0536 and 2484 North Elston Ave - 773-486-8084and 4951 West North Ave. - 773-278-0518 and 7554 So. Stony Island Ave - 773-324-2347 State Street Bread Co. - 30 E Hubbard - 312-595-0766 Subway sandwich shop - with $5 purchase - 1642-44 E. 55th St. - 773-667-SUBS Subway sandwich shop - 1449 E. 57th St. - 773-241-SUBS Subway sandwich shop - 2412 N. Lincoln Ave. - 773-529-0600 Subway Sandwich Shop - 3346 W Foster Ave. - 773-588-9660 Subway Sandwich Shop - 1513 West Fullerton Avenue - 773-281-6699 Subway - 4556 n Magnolia Ave - 773-989-0005 Teal Cafe - 9101 Beverly - 773-238-9501 The Coffee Studio - 5628 N Clark St - 773-271-7881 The Grind - free w/purchase, get password at register - 4613 N. Lincoln Avenue The Heartland Cafe - 7000 North Glenwood - 773-465-8005 The Map Room - 1949 N Hoyne - 773.252.7636 The Charleston Tavern - 2076 N. Hoyne - 773 489-4757 Third World Cafe - requires purchase - 1301 E. 53rd St - (773) 288-3882 Touchvelocity Internet Cafe - 557 S Dearborn - 312-347-1639 United Center - 1901 W Madison St - 312/455-4500 Victoria's - 3224 W. Foster Westgate Coffeehouse - 924 West Madison St. White Hen Pantry - Store #7913-3 - 2757 N. Pine Grove Zen Noodles - 1852 W. North Ave 311 South Wacker - in the Wintergarden, Skylobby, Retail Concourses and Park Hotel 71 - business center area - 71 East Wacker Drive - 312.346.7100 Amalfi Hotel Chicago - Twenty West Kinzie Street - 312-395-9000 Omni Chicago Hotel All Suites Hotel - 676 North Michigan Avenue - 312-944-6664 Omni Ambassador East - 1301 N State Pkwy - 312-787-7200 Talbott Hotel - for guests only - 20 E. Delaware Place Four Seasons Hotel - 7th floor bar area - 120 East Delaware Place - (312) 280-8800 Hotel Allegro - 171 W Randolph Hotel Blake - 500 S. Dearborn St The W Hotel City Center - lobby only - 172 W. Adams St. The W Hotel Lakeshore - lobby only - 662 N. Lake Shore Drive