Reddit mentions of Blues Harmonica Masterclass

don't listen to people saying look at tabs, that's a horrible idea

get an A harp or a C harp, or better yet both. i recommend not being too cheap about your first harmonica purchase, a good harp not only feels way better to play but it's actually much easier to play and master new techniques on too. i strongly recommend:

hohner special 20

after that you just need to learn the basics, there are a ton of really good harmonica lessons on youtube nowadays. harmonica is something you really learn by just listening and playing around, with a few subtle tricks/secrets here or there that need to be told to you.

try this guy:

http://www.youtube.com/user/KudzuRunner

if you want to get decent, I'd highly recommend this:

http://www.amazon.com/Jerry-Portnoys-Blues-Harmonica-Masterclass/dp/B00005KJ36

it comes with CD's etc

all of this is assuming you wanna learn blues harp though

A is optimal because it is not too deep or too high, and it's cross position (blues position) is E, which is very natural for the guitar to play blues from.

Edit: this book is good stuff and it is in the key of A https://www.amazon.com/Jerry-Portnoys-Blues-Harmonica-Masterclass/dp/B00005KJ36

Edit: also check out this site http://www.angelfire.com/tx/myquill/