:sl:
Your best bet would be to join up with any or all of the following dudes (you may have heard of some if not all of them already):
ozzycda - specialises in interfaith dialogue as well as pwning islam haters.
VoyageIslam - Awesome voice and raises a lot of good points.
BonsaiSky - more down to earth approach than the other guys. Good chap too.
Islamandfriends - his bluntness can sting but he knows what he is talking about
SamiZaatari - What can I say that you don't already know about him? Other than he seems to pwn pat condell every chance he gets. Also gets a lot of crap from critics (his videos always have around 50 comments in the first 10 minutes :p) so he must be doing something right!
These guys are probably the best 'lions of Islam' on youtube. There are others, but these in particular stand out. If you cannot defend Islam through dialogue, then at least support those who do via subscribing to them.