I'm having a little trouble setting up a wireless connection. Here's

iwconfig:
[d:b]   ~   #iwconfig
lo        no wireless extensions.

eth0        IEEE 802.11b/g ESSID:off/any Nickname:"Broadcom 4318"
        Mode:Managed Access Point: Invalid
        RTS thr:off  Fragment thr:off
        Encryption key:off
        Link Quality:0 Signal level:0 Noise level:0
        Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
        Tx excessive retries:0 Invalid misc:0 Missed beacon:0

eth1        no wireless extensions.

Elsewhere, I saw the following suggestion:
> iwconfig eth0 up
> dhcpcd

Which gives me:
[d:b]   ~   #iwconfig eth0 up
Error   :   unrecognised wireless request "up"
zsh: 8041 exit 255    iwconfig eth0 up
[d:b]   ~   #

Any ideas on what I should do next?
Thanks in advance,
Alex