There is a time to go all in...but it's almost never at the beginning of a tourney.
Times that it is a good idea...
1. Late in a tourney when you're shortstacked. If you're less than 10XX BB, jam when you get a hand. You'll either steal the blinds...double or triple up...or get knocked out. If you get knocked out, oh well...that's where you were headed if you didn't play any hands anyway.
2. If you have a decent hand, a big stack, and one other person is in the hand and shortstacked...a push will often cause them to fold a hand unless it's the nuts. Sometimes they'll stick with it and get knocked out, which is good for you, too.
3. Often I will play QQ, JJ, 10 10 this way...preflop raise of 3-5XX BB. If the flop comes with no over cards and no flush draw...shove 'em all in. I've even done that once with 77, although I was shortstacked.
Of course all these can backfire, but if you pick your times wisely, they can really work.
But preflop all ins? Almost never until shortstacked. I think it's a very bad idea. 3 things can happen, and two of them are bad.
1. You double up (good)
2. You just get the blinds (okay, not bad, but you might have been able to get more chips than just the blinds, particularly early in a tourney).
3. You get your ass handed to you on the way out the door (bad).