Short answer: Yes and No.
Yes it can work...if you use an all analog setup, and no it won't work if you try to mix analog and USB sound/speakers/headset.
My own system uses an analog Creative Labs X-Fi Titanium Fatality Champion.
This is a high-quality analog add-on sound card plugged into a PCI-E slot, and a front mounted control panel that mounts into a 5 1/4" or 3 1/2" external drive bay, that you plug your ANALOG headset (Headphones & Microphone) into.
It allows setting the speakers to automatically mute when a headset is plugged into the front panel, OR to output sound to both headset and speakers.
Automatically muting the speakers is important in my household as it helps to prevent Wife/Kid ack when I'm playing AH2 and other games.
Be carefull when running both headset and speakers as sound from the speakers can feed into the Microphone and cause a very noisy and annoying feedback loop.
Depending on your speaker setup, plug the Buttkicker into either the Line Out (Green - for 2/4 channel) jack or the Center/Sub-Woofer (Orange - for 5.1/7.1 channel) jack on the sound card's back panel.
See the detailed instructions on Buttkicker's website.
Please also note this important notice from the Buttkicker website:
IMPORTANT NOTE ABOUT USB HEADPHONES / SPEAKERS:
ButtKicker brand products will not work with USB Speakers or Headphones because computers are NOT able to output audio to more than one device at a time. If USB Headphones or Speakers are plugged into your computer, no audio signal will be available using the regular analog mini 3.5 jacks which both the ButtKicker amplier and many external speakers require.
Good Luck.
CptA