<a href="skype:<username>?<action>">Link Text</a>
<a href="skype:myuser?chat">Start chat</a>
<a href="skype:myuser?call">Start call</a>
<a href="skype:myuser?userinfo">See profile</a>
<a href="skype:myuser?sendfile">Send a file</a>
<a href="skype:myuser?add">Add to contacts</a>
<a href="skype:myuser?voicemail">Send a voice mail</a>