Also to get 100% access to any file in your eMule queue (with first/last chunks), as vlc can be a bit buggy I suggest using the eMule part file access module for VideoLAN.
Basically it's a dll file that you put in the plugin directory of vlc and it gives reliable previewing of files.
Find it here :
<a href="http://emule-project.net/home/perl/general.cgi?l=1&rm=download" target=blank>emule project download page</a>
Scroll down to the Extras and additional tools section
Theres a <a href="http://emule-project.net/faq/part_file_readme.htm" target=balnk>read me</a> there too!