How do I connect two wired LAN networks with a wireless link?

How do I connect two wired LAN networks with a wireless link?
What you are looking for is a point-to-point link between a pair of wireless bridges. Wireless bridges are available for indoor and outdoor use; you'll need to select a bridge based on the distance that you want to cover and the obstacles between your bridges.

For example, the Linksys WET54GS5 is an indoor 802.11g bridge with 5 switch ports for connecting wired devices. Using a pair of these bridges, you could uplink each of your LANs to a switch port and provide wireless connectivity between the two bridges, with both bridges located indoors, within a few hundred feet.

Or you could use a product specifically designed for outdoor use, like the Proxim Tsunami QuickBridge. These "turnkey" kits include a pair of bridging devices, outdoor antennas, surge arrestors, and Ethernet cables. You could use one of these kits to connect LANs located in two buildings, with antennas mounted outside.

Or you could use an 802.11 bridge designed to support longer-range outdoor links, like the Cisco Aironet 1400 wireless bridge. Using a pair of these bridges, you can connect LANs in more distant buildings -- according to specifications, reaching up to 8.5 miles (point to point) or farther by adding a high-gain directional antenna. But you'll need to assemble and purchase a list of parts needed for your specific configuration.

You can find a longer list of wireless bridge products at Wi-Fi Planet, along with a short tutorial on wireless bridges.