So I noticed that almost every 'how to use a mod' blog was really hard to understand, with loads of grammatical errors, and other annoying things like that. So I hope to do better, here it is:

1. Get WinRar/WinZip or 7zip, I would provide links, but I couldn't find a decent one.
2. Download a mod. [Most mods need modloader]
3. Click the windows button in the lower right hand corner of your screen, or click on the windows explorer icon/My documents.
4. Search "%appdata% then click on '.minecraft' then 'bin' then open 'minecraft.jar' with WinRar, or 7Zip
5. Do the same with the mod
6. Drag the files from the mod into the minecraft.jar thinng, then close them both and start up minecraft.