Here's one more device you can slide inside your notebook's ExpressCard slot. D-Link's DWL-643 Xtreme N adapter supercharges your throughput by hitting speeds that max out at 300Mbps when connected to an Xtreme N router. The card was designed to automatically detect and connect to any of D-Link's wireless products and is also backwards compatible with 802.11b/g networks. Just remember that you'll need an Xtreme N router to take advantage of the speeds, otherwise save your cash and stick with your notebook's built-in wireless support.
D-Link DWA-643 Xtreme N Notebook ExpressCard USA Bound [Mobile Whack]