clicking web page tab

< ^ > P N |<>|^_>< --- | ~ ...Help

i have a tab on a web page that i want watir/ruby to click.

the DOM has it down as:

<HTML>
 ...
 ...
  <Frame Id=topMenu>
    <FORM id =Form1>
      <TABLE class=tblbg>
         <TD id=tabWrap>
           <DIV class=admin id=header>
             <LI id=nav-plan>

can anyone suggest a ruby/watir command to simulate the click

cheers