My Little Pony Forums:
     My Little Pony Arena - My favorite. Features include trader feedback/support, collection/trader galleries, and much more!
     My Little Pony Trading Post - The new location of the oldest (that I know of) pony forum. No more ezboard; yay!
     My Little Pony Playhouse - I don't go here much, but it's a cute site with lots of forums to post in.
     Fiona's Feedback Forum- A forum dedicated to feedback regarding pony-related transactions.
     Ponyland's Catfights - An off-topic forum for pony collectors. Contains adult language.
     My Little Pony Community Board - I have yet to get to know this site.

My Little Pony Identification:

     The Pony Pledge - A resource for buying, selling, and trading Mlp. Includes the Watchful Eye.

My Little Pony Identification:

   Dream Valley (G1)
     My Little Pony Collector's Website - The best ID site that I'm aware of. I am completely dependent on it.
     Dream Valley - Some information is inaccurate, but a good source for identifying Mlp and related lines.
     The Petite Pocket - A great Petite Pony guide.
     The Complete Princess Accessory Guide - Includes alternate accessories and MIB pictures.
     Sea Pony Utopia! - Focuses on Sea Pony identification and information.
     Playsets - A very good source for Mlp playset accessory information.
     Dream Cavern - Information on Dream Beauties, an Mlp-related line.
     My Little Pony UK Scrapbook - A source for information on ponies sold in the United Kingdom.
     My Little Pony Identification Pages - United Kingdom - Another ID site, created by a UK native.
     My Little Pony Lovers - A source for information on ponies made in Italy (currently being remodeled).
     Mexican Pony Paradise - A very nice site containing information on Mexican ponies.

   Friendship Gardens (G2)
     Ponyland Market - The G2 guide I use.
     Rainbow Forest - Looks like a good site; I haven't browsed through it yet. :P

   Ponyville (G3)
     Ride the Rainbow - The best G3 site I've come across.