A healing priestess has no need for hit rating. Unless someone has silenced you, you are assured of a healing spell hitting your intended target. But what if someone needs you to dps instead? Below you will find some not too hard to attain blue quality weapons with hit rating.
From drops we have these beauties you might be able to pick up while you heal for a group.
Ancient Measuring Rod - from Loken in regular Halls of Lightning.
Wand of the San'layn - from Prince Keleseth in Heroic Utgarde Keep.
From quests, there are no blue rewards with hit rating. But there are a few notable greens. If you are in it just for the stat, these will do for a spell (Get it, spell? I kill myself...).
Wand of Blinding Light - Kill a few Scourge in Dragonblight (Light's Trust area to get quest)
Whelpling-Skull Zapper - depending on your faction, this baby either is from escorting and undead apothecary to safety or from an escort in the Utgarde Catacombs.
Frail Bone Wand - Vereth on the Rise of Suffering in Icecrown wants you to kill Rokir. Here's your reward.
Are you fond of staves? Here are a few fun options!
You might find one in the auction house...
Zabra's Misplaced Staff
or quest for one...
Chilly Slobberknocker - if you do this just for the fun, do it! Funnest quest line ever! This is in the Ampitheater of Anguish in Zul'Drak.
Stave of Youthful Sorrow - Work for Tirion in Icecrown, he'll give you this!
Tower of the Infinite Mind - For Horde, this one is practically a freebie. Apparently, the alliance do a group quest to get this, but they get paid, too.
Some of us prefer having the versatility of a one hand weapon and off hand to compliment.
Flameheart Spell Scalpel - 74 gold and change when you are revered with Kirin Tor. (not hard to accomplish if you are doing profession dailies in Dalaran, and wearing a tabard from 78 on during instances.)
No quest rewards, world drops, or boss drops for this slot with hit rating, unless you want some agility, or this green...
Ritualist's Bloodletter - a little ghost boy in Icecrown has you collect blood from some faceless creatures, and gives you this.
Telestra's Journal - from Heroic Nexus
That's all, unless you don't mind toting a green Manual of the Tides around.
Figurine - Twilight Serpent - Jewelcrafters, this is where you shine. Socketed trinkets. And I stuck with enchanting....
Mark of the War Prisoner - drops off Cyanigosa in Heroic Violet Hold.
Sphere of Red Dragon's Blood - I only mention this drop from Heroic Nexus for the sheer mass of hit rating. The attack power is useless, but if this allows you to use an item with better stats, roll on this. But roll greed. Let that rogue get it first, please?
A notable green mention, Rune of Infinite Power, can be obtained by protecting your past self.
You will want to collect as many of these items as you can. There are no talents that help with hit rating for Holy damage, so at 80, a holy priest would need 446 points of hit to cap.