Have a look at MODMii, its 100% FREE
ModMii for Windows - GBAtemp.net
It explains how to do it with an included guide that is generated when it creates the files needed and I think it has a choice of 3 different ORIGINAL games you can use to install the initial hack to get things started
It downloads ALL needed software and then you just copy it to your SD card and install it following the guides
Very easy to use, 100% offline, which means your wii doesn't need a 'net connection, you just need a 1GB NON-SDHC memory card and a card reader/writer on your PC
When you run MODMii, make sure you choose the 4.3 firmware option and make sure you choose your correct region (PAL/Europe I assume), as the files to softmod 4.3 firmware is different from the others so will fail with an error if you choose the wrong firmware. But it shouldn't brick you wii, so don't worry
Also, be aware that the black/red wii's WILL NOT read DVD-R, so you CANNOT play backups from disc, ever.
You MUST run your backups from either USB or external device
You can replace the internal drive with a new older revision drive that can read DVD-R's but means takingyour wii apart, and apparently Nintendo have got wise to this and the very latest wii's may have different drive hardware that locks the drive to that specific console, but this shouldn't stop the softmod just stops people changing the actual drive