First, you'll need to download the Recovery Disk Assistant app. It's a small file -- a little over a megabyte in size -- and once it was downloaded I opened the disk image and dragged the Recovery Disk Assistant app into my Utilities folder.
Next, you'll need media. The "disk" part of Recovery Disk Assistant is a bit misleading, since you can't actually use a blank DVD. I'd recommend going to your local OfficeMax / OfficeDepot / Staples / Walmart / Target to pick up a 4 GB flash drive. They're cheap -- most outlets are selling them for less than US$10. If you already have one, realize that the Recovery Disk Assistant is going to reformat it, so make sure you take all of your files off of it.
Now fire up the Recovery Disk Assistant app. You'll be required to agree to a software license agreement, so be sure to take some time and read every last word in the agreement (I am kidding). Click the Agree button, and now you'll be asked to plug the flash drive into an available USB port. After noting that your disk is going to be erased, click Continue.
The process takes less than a minute, after which you'll be instructed on how to use the recovery disk in the event of an emergency (below). Basically, if your boot drive is toast, connect the flash drive to your machine, restart while holding down the Option key, and then select the Recovery Disk. You'll have four options available to you -- restore from a Time Machine backup, Reinstall Mac OS X, Get Help Online, or Repair or Erase a disk using Disk Utility.
Under the Utilities menu are three more options -- the Firmware Password Utility, the Network Utility, and everyone's favorite, Terminal. It's so easy and inexpensive to create a recovery disk for your OS X Lion installation that you should not only create one, but seriously think about carrying it on your keychain for those emergencies you encounter while away from home.