I've had a ton of problems related to using wifi with my intel 2915 wifi card. http://forums.fedoraforum.org/forum/showthread.php?p=558619#post558619 Some of the problems are hw/firmware specific, but the 3.0 version of ipw2200 seems to have solved the situation. However, I still have problems switching profiles. Troubleshooting is difficult, and it's hard to figure out which commands/gui tools are taking precedence. For example, I can activate a profile for a wifi device in system-config-network. However, if Network Manager can't successfully connect to a wifi network, it will deactivate the wireless device profile. That seems wrong. Aren't the two things independent? (after all, I can activate the profile without necessarily being connected to a network). I the user am unclear whether I need to reactivate the network device profile again or whether the Network manager will do so on its own when trying to connect to the wireless network.
Either use system-config-network _or_ NetworkManager... NetworkManager takes over everything.