question about using wpa_supplicant with my dell router

[John H.]

hi, i am using zd1211 driver for my usb wireless device, and it is
working fine.  I want to use WPA function on my wireless router, and i
told it to use a ascii characters pre-shared key, wpa group rekey
interval of 300, and TKIP encryption type.  my ssid is
"blah"

after installing wpa_supplicant for my distro, which I did, what would
the conf file entry for this particular ssid be? I saw some examples
talking about a user/pass, but I obviously only have a pre-shared key,
no user/pass.

thanks