http://wiki.eveonline.com/en/wiki/EM#Electromagnetic
*** Damage types to protect against ***

Guristas - Kinetic / Thermal
Serpentis - Thermal / Kinetic
Blood Raider - Thermal / EM
Sansha's Nation - EM / Thermal
Angel Cartel - Kinetic / Explosive / Thermal
Minmatar Fleet - Thermal / Explosive
Amarr Navy - EM / Thermal

*** Damage types to shoot at the enemy ***

Guristas - Kinetic
Serpentis - Thermal / kinetic
Mordus - Thermal / Kinetic
Blood Raiders - EM / Thermal
Sansha - Thermal / Electromagnetic
Angel - Explosive
Mercenary - Thermal
EoM - kinetic
mordu's Legion - Thermal / Kinetic
The Syndicate- Kinetic / Thermal
Thukker Tribe - Exposive