user can choose background color?

[cbtoday]

I see many photoblogs that allow user to choose the background color as white, grey or black. Any tips on how to make this?
Thanks.

[raminia]

see simple template of pixelpost.

[blinking8s]

http://www.alistapart.com/articles/alternate/
http://ppleyard.org.uk/index.php?p=69