What exactly do you want to learn about? TV, cellphones, computers, etc? There's no real guide to everything, but I'm sure all of us here combined could help out when it comes to specific things. Cellphones and computers I could probably help you with myself.
I think you can find video guides on things like excel, although honestly they are very boring.
Just search terms like "Microsoft Excel tutorial" and you should find some.
Try www.ehow.com as well when I was working out how to clean my computer it was the website that had everything I needed on it and Its made a massive difference.