just search for a myspace editor, there are tons of them out there, browse and most of them give you specific step by step instructions about what to do. i sometimes use myspacepimper, mynicespace, ect.

1 — click on "ACCOUNT" just beside the ▼ at the top of a page
(you'll get a new page with black titles and many blue subtitles)

2 — click on "EDIT CHANNEL", the 2nd blue title on the far right
(you'll get 3 different blue subtitles, including "Channel Design")

3 — click on "CHANNEL DESIGN"
(you'll get a new page featuring 9 color combinations at the top)

4 — scroll halfway down until you get all kinds of thin rectangles
(this is the starting point for changing all of your channel colors)

ADVANCED DESIGN CUSTOMIZATION:
Background Color — the far edges and empty gaps
Link Color — the color of anything that's underlined
Label Color — the dates that are inside of brackets
Transparency — how "see-through" the colours are

BASIC BOX PROPERTIES:
Border Color — the short stripe on top of the boxes
Background Color — the color "inside" of every box
Text Color — all text plus the brackets of the dates

HIGHLIGHT BOX PROPERTIES:
Background Color — of the first set of profile boxes
Text Color — of what's inside of those profile boxes

5 — scroll back up to the top, and click on "UPDATE CHANNEL"
(it is on the dark gray stripe, just atop the 9 color combinations)

The changes you make may not take effect right away because
YouTube says there can sometimes be a 6-hour lag before your
channel is properly updated.

Believe it or not, you can actually change your background from
right here within Yahoo!Answers. Just click my direct link below,
and it will immediately take you straight to "YOUR VERY OWN"
channel design. (YouTube may prompt you to first "sign in" with
your username and password):

I hope my step-by-step details is the answer you are looking for.