I think even if someone is using kde, especially kde4, one should use nm-applet instead of knetworkmanager. When I was in kde 3.5, I was using knewtorkmanager and it was working fine. But I should say networkmanager and nm-applet 0.7 have improvised a lot and are a completely different story than 0.6*. In my opinion, you can create gazillion profiles with nm-applet and select one which you want at run time.
[Aside, I should make a general note that over the time, gnome and kde are much more harmonic. (Little while back, I was using kde with lots of gnome/gtk apps like eog, evince, firefox, gnome-mplayer and gecko-mediaplayer, cheese, empathy..., so I naturally shifted to gnome. But I still use kde apps like kate, kpowersave, kile, k3b, smplayer, vlc and what not.) While they have merged some gap, I hope that sometime in future, it should be completely desktop agnostic and one shouldn't be able to say at first glance that its a gtk/qt app.]
Also, I think multiple network cards are supported parallely. On my laptop, both the wireless and ethernet simultaneously get ip addresses (woneder if both can be used simultaneously, but I am sure ethernet is given preference over wireless).
@ KernelOfTruth : Your univ is very restrictive I must say . We have a unsecure connection and just asked a authentication when using browser for the first time. (May be it stores macaddr or some hardware identification and from then on, its not required to logon from any os.) Meanwhile, I am itching to use the newly installed 80211n routers in our dept building .
I want knetworkmanager with KDE 3.5 - I don't use KDE 4.
Would you still mind just trying out nm-applet 0.7 in kde 3.5? (I am curious myself to do it, though I might have to compile a ton on packages to get nm 0.7 in my abandoned old gentoo system having kde 3.5 .)