Well, you could have installed wicd from repos: aptitude install wicd, it will also install all wicd dependencies..It is highly recommended to ask before installing something, it could have saved you a lot of work and problems.
As to having the connection to work, eliminate the "auto usb0 iface usb0 inet dhcp"..You do not need to do it in wireless or usb since you have a plugin daemon which will detect conection of device..It can cause you some problems...Need to read more about network-manager...
As to resolv.conf, this file will always be overwritten by any of this 3 things:
1. Networking Manager
2. Resolv app
3. dhclient
So you need to go to /etc/dhcp3/ and edit dhclient.conf, at the line commented: #prepend domain-name-servers, uncomment it and add your dns, I use the 8.8.8.8 (Google's) and the gateway 192.168.x.x Then just save it and reboot...
You might want to read about dhclient.conf too...
Luck...


