I notice a lot of people use imgburn to burn Wii .iso files. CloneCD is a great alternitive. You can find it on just about any torrent site. Latest version as of 2/28/2009 is CloneCD v5.3.13 works great with the latest Twilight hack funning on 3.4 firmware. Not one bad burn yet. Here is a simple guide on how to use CloneCD to burn your backup .iso files.
Needed Tools:
* Wii * DVD-R Blank DVD or DVD+R Dual Layered Blank DVD (Depending on game size).
* Burner
* CloneCD Version 5 Or Above
Step 1:
Open up Clone CD, anything above version 5 should work. Simply hit the second button. (Select ISO)
Step 2:
Browse to your .iso file and click next. Make sure to select image as the file type as shown in figure 2.
Step 3:
Set your write speed keep it low! 2x or 2.4x and click ok. Chillax for a bit while CloneCD burns the disk.
Step 4:
Put the game in your Wii and enjoy.
Important Notes:
Make sure you burn at 2x 2.4x or close as possible so your game is readable and doesn't skip. This is very important. Memorex DVD-R work great.
FYI I burned a copy of Super Smash Bros. with CloneCD on a Memorex DVD+DL without doing anything special and it worked 100%.
I read that alot of people had problems with this game and use Imgburn to set the layer break. If you still have problems with imgburn try CloneCD.