The Wi-Fi Alliance noted that 10 mobile phones have certified 802.11n built in: I've been waiting a long, long time for 802.11n to appear in mobile phones, and the time has finally come. What the Wi-Fi Alliance didn't mention is that six of the 10 phones are made by Samsung and the other four by LG (you can search by protocol and device type on the alliance's site). It's not a problem; rather, this isn't a sudden industry movement (10 major phone makers each with an 802.11n phone), but it's part of an ongoing trend to make mobile devices faster and more efficient on Wi-Fi networks.
The Wi-Fi Alliance also noted that over 500 handsets have some form of Wi-Fi certification, 141m of which were shipped in 2009 (out of 580m Wi-Fi devices shipped that year). The alliance quotes ABI Research's prediction that 90 percent of smartphones will include Wi-Fi by 2014, as well as a total of 500m handsets with Wi-Fi shipping in 2014.
That's too conservative, is my take. ABI Research knows of what it speaks, but I recall several years ago when predictions were that 75 to 90 percent of laptops would have Wi-Fi built in by some year (2007? 2008?). In fact, the number was well over 95 percent; only a few bizarre outlying devices lacked Wi-Fi. The 90-percent figure for smartphones will likely be hit sooner in the U.S., Europe, and parts of Asia; if inclusion lags, it will be because China won't allow it in smartphones, not because manufacturers and carriers aren't keen to have it built in.