The main item for movement speed is obviously boots. Boots currently max out at 12% movement speed bonus. This only gets you a little under half way to the game cap of 25%. So how do you get the remaining 13%?
Legendary items
Lacuni Prowlers (Bracers)
Slave Bonds (Bracer)
Hammer Jammer(Pants)
Inna's Glory(Pants)
Unity(Rings)
Wanderlust(Rings)mostly Magic Find if not always MF. - i haven't seen a GF stat change up on the ah for it. /remus3
Tyrael's Might(Chest)
Murlocket (Amulet)
The Flavor of Time (Amulet)
Thanks to TheGlow:
Wirt's Orginal Leg - THIS IS NOT LEGENDARY IN THE AH Level 5 Blue Mace - It's hard to find on the AH right now because of the search options. Easiest way is to search for 1H Maces level 5 and then sort by buyout and scroll down to find the cheapest one. Has 6 or 7% movespeed and also has up to 10% gold find and magic find. Only problem is you're not going to be killing anything with it being a level 5 weapon.
This is a list of Set or Legendary items that have movement speed on them in addition to other stats. So what this means is that you need to get probably 2 more items that have has 6% and 7% to complete your set.
Common items that most people look to buy pretty cheap are Unity ring, Slave Bonds bracers, and Hammer Jammer pants. Note that all these items are UNIQUE-EQUIP which means you cannot wear 2 Unity rings at the same time. You will need to pick two different slots. Pants are preferred over Bracers in general because bracers can easily have Pickup Radius which Pants cannot.