With RH 9 and the Alsa drivers I've been able to use an iMic for both input and output.
You need to do a complete Alsa installation, including the OSS portions.
My modules.conf looks like:
# ALSA portion
alias char-major-116 snd
alias snd-card-0 snd-usb-audio
# module options should go here
# OSS/Free portion
alias char-major-14 soundcore
alias sound-slot-0 snd-card-0
# card #1
alias sound-service-0-0 snd-mixer-oss
alias sound-service-0-1 snd-seq-oss
alias sound-service-0-3 snd-pcm-oss
alias sound-service-0-8 snd-seq-oss
alias sound-service-0-12 snd-pcm-oss
With this I am able to record and play with several apps, including arecord, ecasound, and the Gnome Sound Recorder.
