Check specific "text" from a Custom Field and output it, or else do something..

Hi,
So my blog is based on music news and such….

On my custom fields for embedding media. I only allow 2 sources.
– Either Youtube OR a SoundCloud URL

So, i’d like a simple php code that can do this:

[ Moderator Note: Please post code or markup snippets between backticks or use the code button. ]

<?php
Check post meta (get_post_meta($post->ID, 'my_url_media', true);)
?>
<?php if any meta value exist; (continue)
If post meta contains this string "http://www.youtube";
echo '
<div id="JWPlayer"></div>
<script>
    jwplayer("JWPLayer").setup({
      file: "'.POST META HERE (YOUTUBE).'",
      width: "100%",
      height: 30
    });
</script>
';
}
ELSE
{
If post meta contains  "http://soundcloud"
echo '<iframe src=" POST META HERE (soundcloud)" class="somerandomCSSClass"></iframe>'
?>

If there is no meta value, then do nothing at all.

As you can see, i’m a complete php novice, but at least i know how i’d like the function to work.

So PHP & WP gurus, what do you think ?

Thanks for reading