We need a new banner for those who come from /r/SquaredCircle, I'm afraid!
Welcome to /r/mylittlepony! This post contains some useful links and information for first-time browsers. But first, as per custom, Welcome to the herd!
Emoticon guide - How to use pony emotes on our subreddit
MLP Episode guide - Download / Stream all the episodes in HD
Voting guide - Recommendations of what to upvote, and what to downvote.
MLP:FIM page on knowyourmeme - A brief history of My Little Pony, and how it got big online.
Read the sidebar, especially the rules and Pony Reddiquette.
Emotes sometimes have hidden alt text when you hover over them with your mouse.
Friendship is Magic complete series (Google Play)
Friendship is Magic complete series (iTunes)
IDW comics (Comixology) - Friendship is Magic, Friends Forever, Micro Series
Download all episodes, comics, and more - yp1.yayponies.no
Stream of all episodes - http://www.dailymotion.com/playlists/user/MysteriousBrony/1
Largest Pony fanfiction archive - http://www.fimfiction.net/
Largest Brony News site - http://www.equestriadaily.com
Analysis and articles about the show - http://www.mlponies.com/
Largest Pony Deviantart Group http://mlp-fim.deviantart.com/
Reddit Bronies Deviantart Group - http://reddit-bronies.deviantart.com/
Pony picture archives (booru) - (http://bronibooru.mlponies.com/post - http://derpibooru.org/)
Brony apparel (welovefine - the ocular proof)
There are a variety of userscripts available to improve your reddit experience. The linked post will take you to two different sets of emote extensions you can download. Read and use them at your own discretion.
/r/mlplounge - Our off-topic, casual sister-subreddit
/r/mlpvids - Subreddit of pony-related videos
/r/ponypapers - All the Wallpapers you could ever want
/r/mlpdrawingschool - Learn how to draw Ponies from other fans
/r/mlptunes - Subreddit of pony-related music
50 subreddit compilation link - Fifty of the most popular/useful SFW pony subreddits
If you need any help with anything, please feel free to ask!