I have been playing with my wordpress theme, and tweaked it with some php code to add meta tags for description and keywords based on the page title. The description is the page title followed by a hyphen, and then the blog title. The keywords are parsed from the page title, with small words removed. Just edit your theme, and plug this into the header template under the title part (this requires some basic knowledge of html). I am still playing with it, and there is room for improvement.
(If you want a simpler approach, download one of my themes at http://www.zero2rich.com/themes/, and this code is already built in.

<title><?php
$title=trim(wp_title(”,false));
if ($title) {
echo “$title – “;
bloginfo(‘name’);
} else {
bloginfo(‘name’);
echo ” – “;
bloginfo(‘description’);
}
?></title>

<meta name=”description” content=”<?php
$title=trim(wp_title(”,false));
if ($title) {
echo “$title – “;
bloginfo(‘name’);
} else {
bloginfo(‘name’);
echo ” – “;
bloginfo(‘description’);
}
?>” />

<meta name=”keywords” content=”<?php
$smallwordsarray = array(“of”,”a”,”the”,”and”,”an”,”or”,”nor”,
“but”,”is”,”if”,”then”,”else”,”when”,”at”,”from”,
“by”,”on”,”off”,”for”,”in”,”out”,”over”,”to”,”into”,”with”,”this”);
$title=trim(wp_title(”,false));
$keywords=split(“[[:space:][:punct:]]+”,$title);
if (!$title) {
bloginfo(‘name’);
$keywords=array(“”);
}
$c=0;
foreach ($keywords as $k) {
if ($k and !in_array($k, $smallwordsarray)) {
if ($c > 0) {
echo “,”;
}
echo “$k”;
$c=1;
}
}
?>” />