First off, and no offense, but use a dictionary [url="http://www.dictionary.com"]http://www.dictionary.com[/url]
Second, if you think you're gonna get up to a 100 lb dumbell curl (assuming one handed), you're dreaming. Nice incenstive and motivation, but I wouldn't expect you to get there anytime soon, that's just my opinion.
There's many ways to do a bicep curl, and it really comes down to the variation you use, and what seems to work for you. The idea remains the same through them all (... you curl! lol), but there's some specific methods of which people seem to follow. First off, I like to do a full range of motion by standing up and letting the weight hang down, arm fully extended. Then I curl up keeping the upper arm remaining pointed down and just curling the lower arm up as much as I can, and squeezing the bicep when I get to the peak. I'm still working with how I hold the weight though and turning it this or that way. But like I said, find what works for ya. Takes time and experimentation (and/or researching)
My two things I do is 1) I do the full range slowly, and I mean slow, it takes me like 30 seconds (if i'm patient) to do the first rep. Then I go slowly back down, full extention. I do about three of those with a low weight (poundage). This really elongates(sp?) the lower portion of the bicep and gives it good 'length,' especially on a preacher curl. 2) I do the upper half of that range of motion. This isolates the upper part and builds the 'peak' of the bicep. This method use a lot of weight. The idea is that you can't do the full range of motion with this amount of weight, but you can sure as hell do the upper half and it really puts the mass on that condensing and contracting of the muscle at that peak position. I've gotten great results from just these two methods. I really prefer using a bar though and working both at the same time.