I'm reading the Player's Handbook as we speak and was wondering do you get 1 each of at will, encounter, and daily powers per level?
Nope. The chart on page 29 of the PHB explains it. You only ever get two At-Will Powers (unless you're human, in which case you get three). At 1st-level you also get one Encounter and one Daily power. You add one Encounter power at levels 3, 7, and 11 (and as you level after that, you substitute weaker powers for stronger powers). You add one Daily power at levels 5, 9, and 20 (and as you level after that, you substitute weaker powers for stronger powers). You gain your first Utility Power at level 2, and you add one Utility power at levels 6, 10, 12, 16, 22, and 26.
Also what do they mean in some powers under attack they say Strength vs. AC or Strength vs. Reflex?
That's discussed on page 57 of the PHB. But to sum up, that's the attribute you use to determine your attack. Put it this way: When a Fighter made a melee attack in 3E he used Str. Melee attacks were made with Str and ranged attacks were made with Cha. You added those scores to the attack roll. Now you add other scores, instead.
So let's say a 1st-level Fighter makes an attack, and it says Str Vs. AC. He gets +3 proficiency bonus from his longsword, +1 to hit from his Fighter Weapon Talent, and another +3 to hit from his Str 16 for a total of +7 to hit. It's Vs. AC, so he needs to roll equal to or better than the enemies AC in order to hit and do damage.
Likewise, a Wizard casts a spell that's Int Vs. Ref. He gets +4 to hit from his Int bonus and no other bonuses. So he makes an attack with a +4 bonus to hit, and has to roll equal to or better than the targets Ref Defense. If he hits then he does damage. And so on.
