Should be possible, yes. Ventrilo has an option in the "Setup" menu, under the "Voice" tab, to choose which sound device is to be used for each function. For example, I have mine set up at the moment for "Default DirectSound Device" for the output and "USB20 Camera" for input (as when I initially installed it, that was the only mic I had) - changing these to a different setting should only affect Ventrilo, not any other programs.
If, however, you want to change the default sound device for everything on the computer: (Assuming here you have XP)
Go to Control Panel
Double-click on "Sounds and Audio Devices"
Click on the "Audio" tab at the top
Use the drop-down menus to choose sound cards for "Sound Playback" (all output from the computer, unless chosen otherwise in a particular program) and "Sound Recording" (all input)
Click OK to save the changes.
If, at any time, you need to change the volume for a particular audio device:
Double-click on the speaker icon in the taskbar
Click "Options"
Click "Properties"
Use the drop-down menu next to "Mixer Device" to choose the sound card whose volume you need to change.
Click OK, the volume sliders for the chosen device should appear in the Volume Control box.
Hope some of this was of some help.
--J
