If you are an Opera fan and want to enable Flash for it here are the steps you should follow:
1. Install Flash for mozilla using Synaptic Package Manager or dowloaded directly from Adobe site. Once is working on Mozilla follow this steps:
1.1. close Opera if is opened.
1.2. go to /usr/lib/mozilla/plugins/ and copy file flashplugin-alternative.so to /usr/lib/opera/plugins/