[billstelling]

A lot easier to do than write up.. It can be done though but unless you can talk someone into doing it for you I doubt someone is going to take the time to write it up.
Basically you need to identify the unique selectors for the tabs and code in a color for a: active for that a.tab .

a.tab

is the selector for all tabs and the unique selector for home above on this forum is

a.tab:nth-child(6)

you can then add the css for them using those parameters.

and this forums css code for tabs

td.tab a:link, td.tab a:visited, td.tab a:active, a.tab, td.tab2 a:link, td.tab2 a:visited, td.tab2 a:active, a.tab2, a.tab2:link, a.tab2:active, a.tab2:visited {
    background: url("images/cstyle/button2.gif") no-repeat scroll right top transparent;
    font: 10pt tahoma,sans-serif;
    width: 76px;
    height: 20px;
    text-align: center;
    padding: 2px 0px 0px;
    margin: 0px 1px;
    text-decoration: none;
    float: right;
    position: relative;
    top: 3px;
}

you can use it as a template to start with as it has the basic info you need to start with about what is controlling the look to begin with.