Yes, the851N will work with 802.11b, 802.11g or 802.11n networks using almost any off-the-shelf Wi-Fi router. These include Wi-Fi routers from Apple, Netgear, Linksys, D-Link, and others.
Note that if you use an 802.11n router and then connect to it with 802.11b or g devices this will normally force the router to fold- back to an 802.11b or g service reducing the data-rate possible. In other words, the router will always work at the 'lowest common denominator' of b, g or n devices connected to it.
Special routers are available however that are able to maintain dual 802.11b/11g and 802.11n networks.