1. Are they legal? If not then will I get caught (lol)?
Depends what you are downloading. If it is copyrighted material (like the latest movies that hasn't even have a DVD release date) then it would be illegal.
There are some contents however that you can download legally.
2. Are they hard to use?
Nope. You just need to use a Torrent Client like Azureus
3. What do I have to download to use them?
Torrent Client like Azureus
4. Are they safe? (like viruses and stuff)
Hard to say. But most are virus free specially files that are widely seeded.
5. Any other info is helpful!
Here's a list of torrent clients that you can use:
http://en.wikipedia.org/wiki/BitTorrent_client#General
I highly recommend this torrent site:
http://www.mininova.org
Also, a final note, be careful with what you are downloading. specially those contents that you think are questionable.