Microsoft is evaluating a new tool called VirtualWiFi (http://research.microsoft.com/netres/projects/virtualwifi/software.htm) allowing Windows XP users to simultaneously connect to multiple networks using only one WiFi adapter. Microsoft is citing (http://research.microsoft.com/netres/projects/virtualwifi/multinet_infocom.pdf) (PDF) various uses for the technology:

Concurrent Connectivity: A user can connect her machine to an ad hoc network, while staying on her authorized infrastructure network.
Network Elasticity: The range of an infrastructure network can be extended by allowing border nodes to act as relays for authorized nodes that are outside the range of the Access Point.
Gateway Node: A node that is part of a wireless ad hoc network and close to an AP, connected to the Internet, can become a gateway node for the ad hoc network.
Increased Capacity: The capacity of ad hoc networks can be increased when nodes within interference range can communicate by switching on orthogonal channels.
Virtual Machines: Users can connect different virtual machines to physically different wireless networks.


For instance, with VirtualWifi users will be able connect to a guest's machine or play games over one wireless network, while surfing the Web on another. In the realm of handheld computing this technology could prove to be very useful (if adopted), given that most handheld devices are restricted to a single physical network adapter.

[via Engadget (http://www.engadget.com/entry/1234000497063795/)]

This is exciting news for me, especially as I've only just taken the leap into wirelessconnectivity (I'm sitting in my lounge room typing this into my X50v with my BT keyboard through my wifi connection to my PC in the study). This is the life!