I would like change the admin theme header and left column backgound color to match with my front end design.

You guy know where to do the changing?

You can start by reading the themes documentation here:

http://xoopsdocs.net/modules/docs/

just want top confirm again, you mean i need to install the Headlines module than only can do the admin headline configuration?

The way XOOPS is setup, there is in your public_html/themes directory a set of files (notably style.css and theme.html) Almost all modules use all or parts of these to drive their look and feel. Some modules have their own themes, css and the like.

You need to know the following:

1. Are you going to change the whole system? If so modify the public_html/themes files
2. Does your module have its own themes that need modification? If so find them and modify them

If you want to get mor sophisticated than that you can set multiple themes by page for a XOOPS site. Hacks for that are to be found at:http://xoops-tips.com/

If you want to see how all this works, go to my http://eirenicon.org site. Play with the Try our Themes box (bottom left). If you want to download some annotated themes that provide limited instructions on what and where to change things, download those from my site also-- either will work.

Good luck!