Hi,
Nice little plugin, still seems to work fine despite the comment here and the fact that development has stopped.
One thing is that it doesn't play well with qTranslate. If I find another plugin that's being developed and is compatible with qTranslate, I might move to that. Meantime, here's a hack. In seo-slugs.php, just after line 27 (where the variable $seo_slug is first set), add this:
if ( function_exists( 'qtrans_init' ) ) {
preg_match( '/<!\-\-:en\-\->([^<]*)<!\-\-:\-\->/', $seo_slug, $matches );
$seo_slug = $matches[1];
}