Some people may prefer not to have the Blog header and keep their forum logo / banner consistant throughout their site. I know i did.
Here is how to do just that
Please note: This isnt too easy to follow as the actual code can change depending on your logo and setup, but it should help you 99% of the way, always copy your existing code from your header and not mine!
Firstly, lets take a copy of the existing board header... (Just copy it, do not remove or change it from there!)
ACP > Look And Feel > Edit Template HTML > All Global HTML > Global Board Header
Find this bit and copy it into a text file for safe keeping (be aware yours may not match exactly, note the starting DIV and the ending /DIV)
Next visit ACP > Look And Feel > Edit Template HTML > Skin Blog Global > Blog Header
Find this part...
Replace it with...
Immediately above that, add the code you copied and saved from the Global Board Header earlier.
You should then have something that looks like this, plus the existing code before and after all that.
Save it and you should be done.
Screenshot (before)

Screenshot (after)

Here is how to do just that
Please note: This isnt too easy to follow as the actual code can change depending on your logo and setup, but it should help you 99% of the way, always copy your existing code from your header and not mine!
Firstly, lets take a copy of the existing board header... (Just copy it, do not remove or change it from there!)
ACP > Look And Feel > Edit Template HTML > All Global HTML > Global Board Header
Find this bit and copy it into a text file for safe keeping (be aware yours may not match exactly, note the starting DIV and the ending /DIV)
<div class="borderwrap">
<div id="logostrip"><a href='{$this->ipsclass->base_url}'><!--ipb.logo.start--><img src='style_images/<#IMG_DIR#>/logo4.gif' style='vertical-align:top' alt='IPB' border='0' /><!--ipb.logo.end--></a></div>
Next visit ACP > Look And Feel > Edit Template HTML > Skin Blog Global > Blog Header
Find this part...
<div class="borderwrap">
<if="$this->ipsclass->vars['blog_enable_dheader'] == 1">
<div id="logostrip"><a href='{$this->ipsclass->vars['blog_url']}'><img src='{$blog['header_image']}' style='vertical-align:top' alt='{$blog['blog_name']}' border='0' /></a></div>
</if>
<if="$this->ipsclass->vars['blog_enable_dheader'] == 0">
<div id="logostrip"><a href='{$this->ipsclass->vars['blog_url']}'><div style="float:left;"><img src='{$this->ipsclass->vars['img_url']}/logo_blog.gif' style='vertical-align:top' alt='{$blog['blog_name']}' border='0' /></div>
<div style="padding: 15px 0px 0px 0px; color:#FFFFFF; text-decoration:none; width:auto; position:absolute; left:70px; "><b><span style="font-size:24px;">{$blog['blog_name']}</span><br /><br />{$blog['blog_desc']}</b></div></a></div>
</if>
Replace it with...
<!--
<div class="borderwrap">
<if="$this->ipsclass->vars['blog_enable_dheader'] == 1">
<div id="logostrip"><a href='{$this->ipsclass->vars['blog_url']}'><img src='{$blog['header_image']}' style='vertical-align:top' alt='{$blog['blog_name']}' border='0' /></a></div>
</if>
<if="$this->ipsclass->vars['blog_enable_dheader'] == 0">
<div id="logostrip"><a href='{$this->ipsclass->vars['blog_url']}'><div style="float:left;"><img src='{$this->ipsclass->vars['img_url']}/logo_blog.gif' style='vertical-align:top' alt='{$blog['blog_name']}' border='0' /></div>
<div style="padding: 15px 0px 0px 0px; color:#FFFFFF; text-decoration:none; width:auto; position:absolute; left:70px; "><b><span style="font-size:24px;">{$blog['blog_name']}</span><br /><br />{$blog['blog_desc']}</b></div></a></div>
</if>
-->
Immediately above that, add the code you copied and saved from the Global Board Header earlier.
You should then have something that looks like this, plus the existing code before and after all that.
<div class="borderwrap">
<div id="logostrip"><a href='{$this->ipsclass->base_url}'><!--ipb.logo.start--><img src='style_images/<#IMG_DIR#>/logo4.gif' style='vertical-align:top' alt='IPB' border='0' /><!--ipb.logo.end--></a></div>
<!--
<div class="borderwrap">
<if="$this->ipsclass->vars['blog_enable_dheader'] == 1">
<div id="logostrip"><a href='{$this->ipsclass->vars['blog_url']}'><img src='{$blog['header_image']}' style='vertical-align:top' alt='{$blog['blog_name']}' border='0' /></a></div>
</if>
<if="$this->ipsclass->vars['blog_enable_dheader'] == 0">
<div id="logostrip"><a href='{$this->ipsclass->vars['blog_url']}'><div style="float:left;"><img src='{$this->ipsclass->vars['img_url']}/logo_blog.gif' style='vertical-align:top' alt='{$blog['blog_name']}' border='0' /></div>
<div style="padding: 15px 0px 0px 0px; color:#FFFFFF; text-decoration:none; width:auto; position:absolute; left:70px; "><b><span style="font-size:24px;">{$blog['blog_name']}</span><br /><br />{$blog['blog_desc']}</b></div></a></div>
</if>
-->
Save it and you should be done.
Screenshot (before)

Screenshot (after)














