i want to color my hair grey...

ok so i have black hair, i mean as black as it gets i was just wondering if there was a away i could put some grey into it. now i know your thinking what?isnt it usually the other way around?? sure let it be but ehh i dont want all of it grey just like an intresting chunk...help?

Yep, you'll need to bleach your streak until its almost white (the inside of a banana peel is usually the color people go for), then use either more white blonde dye which is violet based (which is bad for your hair after bleach) or violet toner (which will need to be redone frequently, so I don't see how that's any better, but I'm not a pro, that's a question for them).  That will get it platinum white (no yellow), but it still won't be exactly gray.  I'm not sure exactly what combination of stuff you'd use to get real gray.