http://www.smogon.com/dp/pokemon/uxie
I'm surprised this wasn't up already. This is really one of the main reasons that people use Uxie.
[SET]
name: Dual Screen
move 1: Reflect
move 2: Light Screen
move 3: Memento
move 4: Stealth Rock / U-turn
item: Light Clay
nature: Impish
evs: 252 HP / 180 Def / 76 Spe
[SET COMMENTS]
<p>Uxie can use its great defensive stats and relatively high Speed to be a very efficient user of the dual screen strategy. This set works well both as a lead or as a transition Pokemon, and with its impressive defenses, Uxie can take quite a beating from both sides of the attacking spectrum. Behind dual screens, Uxie is notoriously difficult to take down - a Choice Band Tyranitar's Crunch can only manage a maximum of 47% to it, and if you switch, its Pursuit will do the same. This means that Uxie can stay in on Tyranitar and proceed to set up both screens as well as Stealth Rock, if need be.</p>
<p>Memento is really what sets Uxie apart from other Dual Screeners, as it drops the foe's Attack and Special Attack by a further 2 stages, while causing Uxie to faint. This is particularly useful for setting up a sweep with a frail Pokemon such as Belly Drum Charizard, or for Baton Pass teams in need of a little extra insurance. It also means that the incoming pokemon gets in without taking a hit, and is once again very helpful in setting up frail Pokemon.</p>
<p>In the final moveslot, Uxie has a variety of support moves it can use, depending on your team's needs. Stealth Rock is beneficial for pretty much any team, and Uxie's bulk allows it to set it up reliably. Rain Dance or Sunny Day can easily go in that slot for weather teams looking for a reliable replenisher, as can Trick Room. Yawn is a useful utility move for forcing a switch. U-turn is also available for use in the last slot, granting Uxie another way to leave the field without having to sacrifice itself, and also means that Uxie isn't stopped dead by Taunt.</p>
<p>The 76 Speed EVs allow Uxie to outspeed Jolly Tyranitar and Adamant Scizor, both of whom are far less threatening once Uxie is safely behind a Reflect. However, a Jolly nature and maximum Speed can be run, allowing Uxie to set up a screen before many threats expected to be faster than it, in particular Lucario and neutral Speed natured Salamence. Light Clay is the item of choice as it extends the duration of Light Screen and Reflect by a further three turns, allowing the team to make the most effective use of the screens Uxie sets up.</p>
I'm surprised this wasn't up already. This is really one of the main reasons that people use Uxie.

[SET]
name: Dual Screen
move 1: Reflect
move 2: Light Screen
move 3: Memento
move 4: Stealth Rock / U-turn
item: Light Clay
nature: Impish
evs: 252 HP / 180 Def / 76 Spe
[SET COMMENTS]
<p>Uxie can use its great defensive stats and relatively high Speed to be a very efficient user of the dual screen strategy. This set works well both as a lead or as a transition Pokemon, and with its impressive defenses, Uxie can take quite a beating from both sides of the attacking spectrum. Behind dual screens, Uxie is notoriously difficult to take down - a Choice Band Tyranitar's Crunch can only manage a maximum of 47% to it, and if you switch, its Pursuit will do the same. This means that Uxie can stay in on Tyranitar and proceed to set up both screens as well as Stealth Rock, if need be.</p>
<p>Memento is really what sets Uxie apart from other Dual Screeners, as it drops the foe's Attack and Special Attack by a further 2 stages, while causing Uxie to faint. This is particularly useful for setting up a sweep with a frail Pokemon such as Belly Drum Charizard, or for Baton Pass teams in need of a little extra insurance. It also means that the incoming pokemon gets in without taking a hit, and is once again very helpful in setting up frail Pokemon.</p>
<p>In the final moveslot, Uxie has a variety of support moves it can use, depending on your team's needs. Stealth Rock is beneficial for pretty much any team, and Uxie's bulk allows it to set it up reliably. Rain Dance or Sunny Day can easily go in that slot for weather teams looking for a reliable replenisher, as can Trick Room. Yawn is a useful utility move for forcing a switch. U-turn is also available for use in the last slot, granting Uxie another way to leave the field without having to sacrifice itself, and also means that Uxie isn't stopped dead by Taunt.</p>
<p>The 76 Speed EVs allow Uxie to outspeed Jolly Tyranitar and Adamant Scizor, both of whom are far less threatening once Uxie is safely behind a Reflect. However, a Jolly nature and maximum Speed can be run, allowing Uxie to set up a screen before many threats expected to be faster than it, in particular Lucario and neutral Speed natured Salamence. Light Clay is the item of choice as it extends the duration of Light Screen and Reflect by a further three turns, allowing the team to make the most effective use of the screens Uxie sets up.</p>