Almost every Strip hotel has wired access in the rooms.

Currently have wifi in their rooms:
MGM Grand, Mirage, Treasure Island, Mandalay Bay, Hard Rock, Sahara, Golden Nugget, Silverton, all of the Station Casinos (Greeen Valley Ranch, Palace Station, Sunset Station, Santa Fe STation, Texas Station, Boulder Station, Fiesta Rancho, Fiesta Henderson, Redrock Station-opening next April), all of the Coast Casinos (Orleans, Barbary Coast, Gold Coast, Suncoast, Southcoast-opening this December).

Will have wifi in their rooms soon:
Caesars Palace, Bally's, Paris, and Flamingo (a corporate contract to cover these hotels is lose to being signed, these properties already have wired broadband access in their rooms).
THE hotel @ Mandalay Bay is having wifi installed this fall, as is the West Wing at MGM Grand. As stated above Mandalay Bay's regular hotel (3400 rooms) as well as the rest of the rooms at MGM (4300 rooms) already have wifi.

All of these options cost at least $9.99 for 24 hours but it's inaccurate to say there are not places to surf the web in Las Vegas. Even the pool at the Hard Rock has wifi service.