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I take it you're building the theme yourself, or modifying an existing one?

Pay close attention to your CSS floats and the width of the DIVs. Also, validating via W3C can help point out what might be causing it; Also try using the Develop menu in Safari.

If you could be more specific it would be great.

:)
 
Get CSSEdit. http://macrabbit.com/cssedit/ It will help you loads when it comes to fixing problems like this. You can visually see where the problem is, whether you have something not closed, or whatever.

Here are also two PDFs I often refer to:

http://wpcandy.s3.amazonaws.com/resources/WordPress-Help-Sheet.pdf
http://wpcandy.s3.amazonaws.com/resources/Advanced-WordPress-Help-Sheet.pdf

It looks like there are two Meta widgets in the layout. One is hard coded, the other is in the Appearance > Widgets area. Unless there are actually two sidebars.

Look for <!-- Do not change the form action or field names! --> in your header.php or index.php.
 
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