Hey there hunny!
i'm a hair dye junky and I have personally stipped my hair from black to blonde!
I used russel Jerome blonde/hair lightener kit, its about £4 from wilkinson and it works a treat!
I have also changed my hair from black to brown, or to red, green etc!
the process all begins the same way, with a peroxide kit, be warned though it can make your hair brittle and snap off (been through this myself)
After you have used the peroxide its best to leave your hair for a few days, so perhaps do it on the weekend so if it goes wrong at least you can hide in bed.
after a few days, or if your not bothered, then you can put a colour on top, go for a conditioning, nourishing one like garnier!
after you have done this make sure to deep condition your hair at least once a week to get it to its normal state!
you might not have a problem but because you have to leave the peroxide on so long it does tend to dry out your hair!
another option is spend a huge amount of money at the hairdressers or leave your hair to start growing out!
00o and one more tip, washing your hair with washing up liquid helps to get rid of your dye so try doing this before you start anything xx