Grooveshark has a large collection of songs and classical music. You can insert a single song, or create and insert a playlist. The embed codes they provide cannot be used directly in a wordpress.com blog, but they can be converted into a working shortcode (see here for general background).
A. Single song
Search for the song you want. To get to the embed code when the list of results is fetched, click on the title of the song, click “Share Song”, click “Widget” – or click the checkmark next to the song title, hover over “Share Song”, click “Widget”.
Copy the embed code. It will look like this:
Copy the part I have highlighted and turn it into a shortcode this way:
Paste into HTML post/page editor, or in a text widget for your sidebar.
Width can be changed. You can also change the player skin by replacing style=metal with style=wood or style=water or style=grass:
Note: You can insert several songs instead of one, by pasting several song ID numbers together (separated by commas). But the player won’t display all the titles together, so you’ll have to type them in the post. So better use a playlist in that case.
To create and save playlists, you need to have a Grooveshark account.
After you create and save a playlist, click “Share Playlist”, click “Widget”, select a basic color scheme, copy the embed code.
Turn it into a shortcode as shown above, only use widget.swf instead of songWidget.swf – plus the height will be different, of course.
Width can be changed. Optimum height depends on the number of songs; but you can limit the length of a very long playlist (in that case you get a scrollbar, as in the image below).
If you want to fully customize the colors, you need to change the hex numbers manually. Here’s which part of the variables corresponds to which area(s) of the playlist player (“…h”= same item when hovering over):