KNemo offers a network monitor similar to the one found in Windows.
For every network interface it displays an icon in the systray.
http://www.kde-apps.org/content/show.php?content=12956
Note: There are two extensions to the original KNemo:
1. Multiple IPs on devices are supported
2. The semantics of not available devices were changed
from: "device is not up"
to: "device is not up" or "device is up but has no carrier/is not
associated"
which mimics the behaviour of the Windows counterpart more closely
Bugs: The stats page for wireless specific statistics doesn't work, yet