THIS IS NOT MY GUIDE.
But seeing as how there is an extremely old and outdated thread on wii modding and people looking for a new guide, this guide is amazing. It's one for the easiest to follow, and all the files that are needed are in one simple folder, ready to be copied to the SD card. It doesn't get much simpler than that.
Here is a good guide if the wii hacking terms are overwhelming you:
A couple notes I would personally like to make:
The latest bootmii (v0.3) has a huge bug where NAND backups made by it can't be restored. Unless you are confident you won't brick your wii, I may advise trying to dig up the old v0.2 version.
If you can install bootmii in boot2, Preloader is NOT necessary. In addition, it makes your wii menu load more slowly by a couple seconds. However, if you want extra hacks such as region free games and channels, skipping cd update checks, removing the health warning, and moving the disc channel, you'll need preloader.
As a note, after you install preloader it may seem that you have bricked your wii if it gives you an error message when you return to the system menu. If thats the case, that normally means the correct system menu IOS isn't selected in the preloader (scared the shit out of me when I first tried it). If you follow the guide and update accordingly, your systemmenu IOS will be IOS60.
As for additional software, I would reccomend WAD Manager (link in thread) for installing channels(such as usb loader gx forwarder so you don't have to start homebrew to use it) and VC/WiiWare games (such as super smash bros 64, mario kart 64, ect.). In addition I personally think USB Loader GX is the best backup loader, great gui and interface, very simple to use. And as a side note, USB hard drive is definitely the way to go over burning DVD's, with the usb drive the games load MUCH faster (not to mention backup DVD's don't even run as fast as the original games). As for adding games to your HD, use WBFS manager to format your drive to WBFS and addgames. It's very simple, auto scrubs the game, and can auto-extract from a RAR. If you still want to transfer data from a computer, you could have a separate partition for say WBFS and FAT32, and manage it that way.