I'm using CentOS5.2 and I need to connect to a wireless network using WPA. The card I have uses an RTL8180L chipset, so I upgraded the kernel to 2.6.28 kernel which should support that. It sees the card when I run iwconfig.

Also, this is the wpa_supplicant command I'm using:
wpa_supplicant -Dwext -iwlan0 -Bw -c/etc/wpa_supplicant/wpa_supplicant.conf

using wpa_gui, I can scan for the network, and it sees the correct network, but it can't associate with the AP. If I bring up the network using the simple ifup wlan0, it can't get an address.

Let me know if there's something obvious that I'm missing.

Problem solved. Everything was configured correctly, but the signal strength was not strong enough to authenticate.