http://www.smogon.com/bw/articles/ou_sun
Dragonite
The original Dragon-type spent the last two generations being outclassed by Salamence and Garchomp, and with the current presence of Latias and Latios in OU, one may worry for Dragonite. Such concern would be misplaced, however: Dragonite is yet another Pokemon given a new lease on life by its Dream World ability, Multiscale. This grants it far easier setup, complementing its naturally impressive special bulk to make it a viable bulky sweeper. A combination of Dragon-type STAB, Fire Punch, and Earthquake provides Dragonite with perfect neutral coverage, but it can forgo the latter for ExtremeSpeed to revenge kill faster threats. While Dragonite doesn't appear to gain much from sun except a marginally stronger Fire Punch, it can make use of sun in a less expected way: the removal of passive damage from sandstorm or hail reduces Dragonite's need for Leftovers, allowing it to run alternative items such as Lum Berry. In return, Dragonite's great set of resistances, especially to Ground- and Fire-type moves, covers many common weaknesses of conventional sun sweepers.
Salamence
Where would any list of offensive threats be without Salamence? While one of the most threatening sweepers of DPP has somewhat fallen from grace over the generation transition, Salamence still holds its own as an offensive wallbreaker with useful defensive capabilities. Many Dragon-types appreciate the boosted Fire Blast or Fire Fang sun grants them, but Salamence is one of the better choices for a sun team. An immunity to Ground-type moves, a resistance to Fighting-type attacks, Intimidate to cushion physical blows, and the base stats to provide both offense and support lets this notorious Dragon-type fill a variety of niches. Given many sun sweepers' vulnerability to hazards and recoil damage, as well as their general frailty, offensive Wish support is invaluable; however, familiar offensive Dragon Dance or MixMence sets work just as well.
Rhyperior
Though an uncommon sight, Rhyperior is interestingly enough a decent choice for the role of a sun team's physical tank. It packs a useful resistance to Fire-type moves and an impressive base 130 Defense backed up by base 115 HP, and can even tank the occasional Water-type attack with Solid Rock and sun support. Its possesses a wide range of hard-hitting attacks, typically dual STAB EdgeQuake and Megahorn; additional options such as Substitute, Rock Polish, or Swords Dance, as well as Stealth Rock, make for a fairly versatile threat that can be tailored to cater for your team's individual needs.
Snorlax
Snorlax can be a hard-hitting special sponge on a sun team, as its base 160 HP, base 110 Special Defense, and Thick Fat ability let it tank special attacks—Fire-type hits in particular—with ease. It has access to powerful physical moves, including Fire Punch to abuse in sun. Pursuit lets it deal with opposing Psychic- and Ghost-types, particularly Latios and Latias. Earthquake supports its sun-abusing teammates by taking care of Tyranitar and Heatran. A solid Fighting-type resistance is a good idea if running Snorlax, however, as it tends to lure in the ubiquitous Fighting-types that can often pose a hazard to your team.
Mamoswine
Another interesting offensive choice (despite not actually taking much advantage of sun) is Mamoswine, which nevertheless excels at removing one of sun's major obstacles: Dragon-types. These common Pokemon are huge defensive threats, for they resist the two main attacking types of a sun team, Fire and Grass, and are of course formidable attackers themselves with towering offensive stats and excellent neutral STAB. Mamoswine can easily dispatch these threats with Ice Shard, provide varied coverage with powerful Ice-, Rock-, and Ground-type moves, and also play the role of a Thunder Wave absorber. Lastly, it has access to Stealth Rock, which enables it to provide entry hazard support if required.
Zoroark
One of the most unusual Pokemon introduced in BW can be an excellent addition to sun teams. Zoroark's ability Illusion, enables it to disguise itself as the last Pokemon in a party. Sun teams can capitalize on Illusion in various ways, for instance, Zoroark disguised as a Chlorophyll sweeper such as Venusaur, can lure in general threats to sun teams such as Latios, Latias, Heatran, and Tyranitar, all of which Zoroark can KO with its Dark-type STAB attacks or Focus Blast, granting the actual Venusaur on your team and any other sun sweepers, an easier time sweeping the opponent's team. When using Zoroark, especially on sun teams, the player must be wary of abnormalities in regards to entry hazards: Zoroark isn't 2x weak to Stealth Rock, or absorbs Toxic Spikes like some of the Pokemon you may want to disguise it as. Zoroark has access to Flamethower, allowing it to abuse the sun, and its strong priority Sucker Punch can prove very useful to sun teams, as it can be used to dispatch Choice Scarf users such as Landorus.