If you host your blog (via FTP), you can add PHP in your Template code.
One example, if you include smilies in your posts titles, you can "catch" the title using this code:
code:
$PostTitle = <<<PTL
<$BlogItemTitle$>
PTL;
It is important that you use that method, and not the usual $var = "value"; because it might give errors. Then you can simply replace.
Btw, I can't remember the Blogger Tags too well. But they have their guide in the help section (in case you haven't seen it).