McAfee does not have a specialized version of antivirus or firewall software designed for wireless setups, but they do suggest McAfee Wireless Home Networking Security, which provides additional security to a wireless home network that the standard AV and firewall do not provide. It's up to you whether or not you choose to purchase the additional software, but you'll need antivirus software and a firewall as a minimum.
If you like McAfee you can purchase a 1-year subscription, or you could go with one of McAfee's competitors, such as Avast, AVG, eTrust, Norton, ZoneLabs, etc. Each one has a free trial available from their respective websites so you can choose which one you like best. (Just uninstall the one before installing the other.) It's also good to note that Avast antivirus, AVG antivirus, and ZoneAlarm firewall, each have free versions of their software. Some of the features are disabled, but the basic protection is still there.
Finally, you'll want to install a couple of antiadware and antispyware programs to complete your security setup. You can click here for the full list, with AdAware, SpyBot S&D, and Microsoft Antispyware (beta) being the most recommended free applications that will get the job done.
Hope this helps,
Just got a new Toshiba Notebook PC. It came with a standard McAfee Security Center. It's a free trial version. Once this expires, is there a version of McAfee Virus Scan made especially for wireless connections and would it be necessary to get a "wireless" version?