Description of problem: I have a normal automatic ethernet device. It's connected, with IP, etc. Randomly afterwards, NM will connect via wireless, completely hosing the system (there's nothing in resolv.conf, for example.) Version-Release number of selected component (if applicable): NetworkManager-0.7.0-0.9.1.svn3417.fc9.x86_64
Similarly, on wireless it will go into bozo mode where it drops the default route and DNS connection as well - presumably it has something to do with attempting to bring up the (disconnected) wired interface.
There were a few issues with DHCP rebinds blowing away the default route that I fixed yesterday. That's likely what you're running into.
*** This bug has been marked as a duplicate of 437138 ***