recommendations and sites?

Hello,

Hoping some of you can help me out with some recommendations

I'm a fairly technical guy, but know little to nothing about radio
scanning/frequencies. To make a long story short, i'm a freelancer
photographer looking for an edge when it comes to breaking stories.

What I am looking for:
-handheld model
-earphone jack
-all emergency services (im based in Toronto, Canada. I need to cover
Toronto, but I also travel the US alot)
-maybe something that can be programmed from a computer

While i've found some good info on the net, does anyone know where I
can find a basic "primer" on understand radio frequencies?

For example, I was under the impression that a scanner can scan
"everything". I guess a scanner can't scan Cb-radio , FRS/GMRS as well
as emergency services?

Are there radio scanners that can scan more then others?

many thanks