My brother and I normally play network games like Starcraft. Below is some information about the units from Protoss. If you want some infomation on Terran units click Here. Or if you want to see some information on Zerg click here.

Protoss is my favorite race out of all the races, terran second. Protoss is the strongest of the races and each one of their units have a shield.

Zealots are Templar warriors who haven't reached the uper levels of Khala yet. Thhis land unit and all other protoss units have shield that makes them stronger that Terran and Zerg. The only thing that can get rid of the shield besides attacking it, is the Terran science vessel's EMP Shockwave.
Weapon: Psionic Blades.

The dragoon is another land unit, but it can also attack air units aswell as ground. The Dragoon takes a while to reload its gun and is practicarly the same as a photon cannon but it can move. The Dragoon is a warrior who has been hurt or crippled and has vulunteered to continue fighting.
Weapon:Phase Disruptor.

The High Templar is a land unit that can attack air units also. when fully researched they can cast spells like a Psionic storm which sends out ripples through a raw phychic energy storm that destroys the enemy's minds. This spell is very effective, but be careful your units aren't in the storm aswell. Another spell is Hallucination which u cast on one of your own units which u can use either as a distraction when u're attacking and a scout. Hallucination's can't hurt anything and eventually disintergrate. The last spell is when u have to select two templars and make them merge together to make an archon.
Weapon: Psi Assualt.

The archon is the strongest of all the Protoss Units and by far the most impressive,(visually) well i think so anyway, but be careful cause if the enemy does a EMP Shockwave on you the archon is almost dead so if that happens get it back to he HQ and recharge it's shield in the 'shield battery' building. The archon can attack both land and air units.
Weapon:Psionic Shockwave

The Reaver may not look very impressive, but this big slug is very strong. It shoots little scarabs that twirl and twirl until it hits its target. This unit is very expensive because for every scarab u shoot it costs u 15 in mineral may not be much so far but it does become expensive when u keep buying em. Another good thing about a reaver is the same as a carrier and that is it can build at the same time as moving and attacking.
Weapon: Scarab drones.

I love this unit, it works great on air units and isn't that good on land units but when u have say two divisions of 12 scouts each, they are very effective, expensive but impressive. These scouts are also very fast when upgraded.
Weapon: Dual Photon Blasters Anti-Matter Missles

A shuttle can carry any land unit anywhere where u might want to land. This heavily armored bug is very strong but be careful cause if they blow up u lose whatever is inside them.
Weapon: none

Arbiters are also one of my favorites cause i love using their Stasis Fields, it bails u out of trouble when u're enemy is attacking u with a division of seige tanks or whatever and it really annoys them when their units suddenlky turn into ice cubes, but be careful cause they can still repair their units. The Stasis Field turns about 3-5 units into stasis mode which can work to pause your enemy or protect u. The Arbiter's other spell called recall lets you make a rift where u're units are standing and it transports them to where u're Arbiter is waiting for them to appear, but be carefull not to waste this cause it takes up alot of energy so make sure u select all the ppl u want to teleport and move them all into the center of the rift.
Weapon:Phase Disruptor Cannon.

These carriers are very nice too, but they are very expensive. They build up an army of lil interceptors which fly out and kill the enemy who is trying his/her best to kill em while the carrier inself is building more lil interceptors. Carriers are very strong and attack very effectively. The very good thing about these big floating ships is that they can move while they are attacking. If you turn up to be against one of these things dont bother trying to kill the intercepters and aim at the carrier moving around. A good way to scare u're enemy is to make an army of hallucination carriers and send them pretending to attack, but the enemy normally finds out that the marine you're attacking is invincible.
Weapon:Interceptors

The Observer is very useful cause it detects cloaked units and scouts. The observer is the only cloaked unit Protoss have.
Weapon: none