http://www.blog.web6.org/add-logo-to-twenty-ten-wordpress/
7. Look for header.php and copy paste the content to html editor (notepad or notepad++).
8. Look for this code on line 49 until line 52, and delete it. (i said 57 instead of 47 lol!)
<<?php echo $heading_tag; ?> id="site-title">
<span>
<a href="<?php echo home_url( '/' ); ?>" title="<?php echo esc_attr( get_bloginfo( 'name', 'display' ) ); ?>" rel="home"><?php bloginfo( 'name' ); ?></a>
</span>
</<?php echo $heading_tag; ?>>
Replace it with:
<h1 id="site-title">
<span>
<a href="<?php bloginfo ('home');?>" rel="home" title="<?php bloginfo('name');?>">
<img src="<?php echo bloginfo ('template_directory');?>/images/logo.png" alt="<?php bloginfo ('name');?>" />
</a>
</span>
</h1><!--end of h1 site-title-->
This is how your code of header.php will look like.
8. Paste all the code back to header.php, click “update file” and refresh your blog. Logo should be displayed but it has border.
9. Next is go back to dashboard/appearance/editor, and find style.css. Open it with notepad++, find line 32.
Delete these two lines of code:
border-top: 4px solid #000;
border-bottom: 1px solid #000;
Replace it with:
border:none;
your code should be look like in the following image.
10. Paste the code to style.css back again, “update file”. Refresh your page, and the logo should be displayed.
That’s how if you want to replace the title or add logo to twenty ten wordpress 3.0. I hope you like it!