I love free music downloading as much as the next person, and used Limewire for years.
HOWEVER, if you live in the U.S., it's just getting too dangerous. I wouldn't use it, or any other P2P if I were you. The RIAA has tracking programs, which it can legally use to trace where songs go over these programs to your ISP. It can then court order the ISP to give them your personal info, so they can come after you. As a college student, I used to think I was invulnerable, but in the last year, they've cracked down, and I've seen many people I know get sued. The college tried to protect them, but if they didn't erase the files when the college warned the RIAA was knocking, they got served.
And if you think that they only come after the big downloaders, that's not true. My housemate, using Limewire, downloaded only 25 songs, and she was traced and the RIAA tried to get her name from the school. Luckily, she took the school's warning and cleared her hardrive before her user info was called up. However, if you're not in school, or if you're school doesn't care, you're unlikely to get this warning. I think the going price right now is like, thousands of dollars PER SONG.
I hate the fact that I can't download songs for free anymore, but 99 cents an mp3 on iTunes is better than a lawsuit. Also if you drink Pepsi or Coke, they give away free iTunes downloads as a promotion.
Limewire isn't shut down because the RIAA has found it more effective to attack individuals than programs. If they shut down Limewire (a la Napster), another program will just pop up. But suing kids makes people scared. Well, I held out, but its worked for me. Make your own choices, but beware.