Off course. Buy any wireless router and connect it to the modem (I'm guessing it's external) . Connect a PC that can access the internet through your modem to the router (using a regulare UTP-cable). The router will clone your computers' mac-address (and will thus 'pretend' to be that computer). Then you can setup the wireless and you should be up and running within half an hour.
PS. Use a security key on your wireless. WPA is usually the best (unless you're willing to set up a Radius server...)
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