Most mixing boards will have AUX sends or TAPE or HEADPHONE outs the sound guy can use for your feed. Assuming he can send a mono mix of everything you need to an XLR out, you can use a short XLR cable and any "plug-on" or "butt plug" style transmitter meant for hand-held microphones. You may have to switch the level from MIC to LINE, but (as cg says) most such wireless rigs can handle either type of signal.

If your feed isn't provided on an XLR (maybe it's a quarter-inch guitar- or headphone-style cable), you may need need plug adapters and/or "gender changers" to complete the connection. And of course, you'll still have to mount the receiver to your camera and worry about the possibility of radio dropouts, interference, dying batteries in the Tx and/or Rx, etc. etc.

I agree with the advice already given: unless you can borrow the wireless rig (or rent it very cheaply), IMHO a digital recorder like the Zoom will be cheaper, more reliable and more versatile.