I've always used Punky Color. It's similar to Manic Panic but easier to find here.

Here's a photo of me after I used Punky Color:




I have black hair so I usually bleach twice over a couple days (and condition lots!) The lighter the hair, the easier it is to take. They're supposed to be "semi-permanent" but I've found that they actually last longer than regular hair dyes. I think the tub says to leave it on for 15 minutes or something like that.. but since it's non-damaging to your hair, I leave it on for hours.