My Ubuntu machine can connect to my WPA network, but there's not a trickle of internet to be found. It works fine with another (but farther) WEP network.
Windows system on the WPA network work fine (I'm using one to write this question). Wired connection to the router broadcasting the problematic network is also fine.
Do note that I did not try to connect to network using Windows on the same machine. It's an Atheros card - I will include more details if requested.
Oh and I the other systems on the network are visible as well.
EDIT I've removed the Ethernet details from the following output:
~$ sudo lshw -class Network *-network description: Wireless interface product: AR5001 Wireless Network Adapter vendor: Atheros Communications Inc. physical id: 0 bus info: pci@0000:03:00.0 logical name: wlan2 version: 01 serial: 00:22:69:18:f1:d3 width: 64 bits clock: 33MHz capabilities: pm msi pciexpress msix bus_master cap_list ethernet physical wireless configuration: broadcast=yes driver=ath5k driverversion=2.6.38-8-generic firmware=N/A ip=192.168.2.7 latency=0 link=yes multicast=yes wireless=IEEE 802.11bg resources: irq:18 memory:55200000-5520ffff