UWorldPvP displays enemy spec and gear rating on mouse over. It warns when untargetted enemies cast spells at you, and shows the approximate location of every enemy player on the server within combat log range of any player with this addon.
Nearby enemies and their information is placed in a window. The gearscore and inspection mouse over features also work on players of the same faction. In addition, it will also show the percent of their gear rating comes from PvP gear.
Warning messages are displayed in the middle of the screen when any enemy you are currently in combat with, but not targeting starts to cast a spell. It will also warn when any nearby enemy stealths.
The mapping feature lets you see the location of any enemy within combat log range or moused over by any player on your faction who has the mod. The position appears as a red dot on your map of the zone. It currently set to only show players seen within the last minute to prevent clutter. If you are able to get a large enough install base for your faction you should pretty much be able to see any player anywhere.
Notes: Enemy gear rating in PvP zones only works accurately on level 85 players. I'm currently working on expanded BG support and features.