I like roundcube webmail…
But there is no pgp plugin
I googled a little bit and found an trac entry that the developer of firegpg
is working for a plugin for roundcube
firegpg is a plugin for firefox which encrypts the data in a textfield with gnupg
It works fine with roundcube….
mark the content and then rightclick -> firegpg -> do singning or encrypt or blah