The IGH cable disconnects without tools. You can leave the shift chain dangling, just be careful to not damage it. If you're curious, it unscrews easily from the hub. JUST DON'T LOSE IT! After that, just use 15mm box-end wrench to undo the bolts and drop the wheel out. Note the position of the cable in the quick-connect thingie, so you can position it correctly (length) when you re-assemble.

Edit for a PS: While you're there, dribble a few drops of oil down the chain and into the inner workings. Lubing it regularly keeps it running!