Hello,
I wanna become a writer for SNL. What kind of writing sample do I need
to prepare? Who do I
send it to? I heard that Lorne Michaels will take unknown talent. If
that is true, that is good. I am unknown but I truly feel I can do
it cuz I got the talent. Help me out. Thanks.

There are probably many ways to get to SNL - this
is just one suggestion:
Many of the performers and writers have one thing
in common - improv. So much so that the majority
of writers and performers of SNL have attended
improv schools like Second City:
http://www.secondcity.com/
The skits from SNL typically come from current events
or characters that the performers have in their repetroire
and have performed prior to coming to SNL.
The current events stuff is written at a breakneck pace.
Which means you have to be able to be funny
on the spot. Which ain't easy.
So, how can you become a writer for SNL?
My advice - take the improv route.
The improv community is full of stand-ups, actors
and writers who are honing their craft. 
The good writers and performers get noticed
and get offers.
Unlike other TV shows, SNL goes through tons
of ideas a week. Many are disgarded. Some are
reworked. Few are chosen.
Having a few funny skits as samples may show you
can write but doesn't show you can perform
under pressure. SNL is a pressure cooker.
Try contacting Second City and ask them how
their former students have been able to get a
gig on SNL. They'll have a winning formula.
Hope this helps.