This is always a question that I have for those I encounter in the emulation community.  How did you discover MAME?
For me, it was pretty simple.  It was the fall of 1998 and I had just gotten onto my network at college.  (Freshman year where I was introduced to a LOT of things.  
  
  
 ).  I went and got a TON of MP3 files as well as Grand Theft Auto.  (The Original.  God knows how many hours my friends and I wasted killing each other in that game).
I wanted to get a copy of Mortal Kombat since I loved playing it in the arcade.  So I went onto the 
www.dogpile.com search engine and searched for "Mortal Kombat Arcade".  On the first page, I found a link to the mame.net forums.  I then learned about how I could play the original arcade game on my computer!  I couldn't believe it.  I downloaded MAME, downloaded the ROM and had no idea what I was doing.  I registered on the forums and got the living hell chewed out of me.  I then learned that 90% of all people on emulation forums are ass-holes and aren't willing to help out the new people.  A couple of people, however, were willing to help and politely directed me to the FAQs.  I read them all, did more reading, and eventually figured it all out.  Soon, I was playing MK and SF2, and all the arcade games I remembered playing as a kid.  I was in heaven.  Soon, I learned how to compile MAME myself and eventually get rid of all the things that annoyed me.  I was in heaven.
Now, I'm building my own arcade cabinet and when all is ready to go I'll compile a personal copy of MAME with all the tweaks I want in order to play all the games I want.
Still, to this day, I will always remember sitting on my bed in my dorm room as I loaded up Mortal Kombat for the first time on my computer.  It was like heaven.  I couldn't believe it, and to this day I still can't.
So how did you all get introduced to MAME and emulation in general?