socks, worsted wt. & fingerling yarn confusion

[VictoiseC]

Hiiiiiiii! Hm. Ok, I have a question that I'm sure I could probably find an answer for but would like your opinions anyway.

I'm not sure exactly what the difference is between worsted weight and fingerling. I guess the one is much thinner and lighter.
Is that all? I just finished that first pair of socks finally and I used
Peace Fleece. They are gorgeous, but they are HUGE.

(the picture is over in Recently Finished Projects, a big green sock)

My husband tried the finished pair on last night and went BERSERKO over how fantastic they feel. (I think he'll be buying me needles and yarn wo grumbling now) So, it looks like I might have to give these to him and make my own pair. My other question besides the above, about the weight of yarn, is
has anyone made this pair of socks from that book Knit Socks!?

It's on size 3 needles, and a cast on of 48 stitches. Amy, you probably know this in your sleep: is it difficult to size down the pattern? LIke do 44 stitches or 36 stitches so it's dividable by 4 needles. (I use 5 needles). I'm worried about the end when decreasing, how to make sure the stitches are the right amount.

I'm going to get Elizabeth Zimmerman's book...I want to learn how to knit something without a pattern! How cool that must be.

Ok, enough ruminating. Thanks for any suggestions/insights.