Yes,
To change the theme that jPlayer (the framework jammer is built on) uses, you must upload jPlayer themes to this directory:
– (plugin-dir)/jammer/files/skins
“Plugin-dir” is the directory wordpress stores plugins. For my installation the directory is wp-content/plugins. Say you have two skins, in two folders:
jammer/files/skins
– theme1
– theme2
In the shortcode, you can specify which theme you want like: [jammer … skin=”theme1″] if you wanted to use theme1. I recommend not using spaces in the directory names, as behavior in that scenario is not tested.
To change css, use jammer like this: [jammer style=”float: right; (more css here)”]
Let me know how that works!