The Harajuku girls still come out on weekends, but not in the huge numbers that they used to. It's the same with the bands at Yoyogi, they are still there, but less than there were years ago.
Sunday is the day when the cosplayers hang out on the bridge, but you will also see quite a few lolitas and other fashion types walking around the Takeshita area on Saturday or Sunday.
I was out there last weekend and the bridge was pretty empty because of the heat, but some of them were walking on Takeshita and around LaForet.
Even during the week, after school, you are likely to see some of the Harajuku girls dressed up and shopping for clothing and accessories in Harajuku.
If you want to see Japanese girl fashion, don't forget 109 in Shibuya. You can go in there and be shocked every time.
But it's not Harajuku style, of course.