Taking Glocks apart is (mostly) not very difficult. There are good guides online, for example at Glock Parts and topglock.com. My experience begins and ends with my 3rd Gen Glock 19, but it's my understanding that the other models are very similar. The Glock Parts guide claims that 9mm Glocks don't have a "locking block pin", and the topglock.com guide has photos of a Glock 17 which does not have that pin. Well, my (9mm) Glock 19 does have one; it's recent. I haven't looked up which generation they changed it at.
Anyhow. The only difficulty I've had is removing the trigger pin. (Update: A commenter informs me that his G17 doesn't have this issue, though his G19 does) A narrow part of that pin goes through a hole in the forward end of the slide stop lever. The slide stop spring pushes the edge of the hole downward against the pin, such that when you push the pin sideways, the edge of the narrow part of the pin catches against the edge of the hole. The directions I've linked talk about "jiggling" the catch, or "mov[ing] the slide stop lever up/down/back and forth", but that's all a bit vague. There's a wonderful variety of wrong ways you can move and jiggle, all while applying excessive force to the end of the pin and accomplishing exactly nothing.
The exact relationship in there becomes clear when you finally get the pin out: The forward end of the slide stop is pushed downward by its spring. What you need to do is hold that end of the slide stop up while you push the pin out. Given the way it's hinged and where the spring is, any kind of normal jiggling is likely to push the forward end down, not up.
So here's the trick to it: There's a tab in the middle of the slide stop lever. It extends inward. It's there so that when an empty magazine is in the pistol, the magazine follower pushes up against that tab, which engages the slide stop.
You need to get your left thumb on top of the external slide stop thing, and your left forefinger under the tab. Push down with your thumb while pulling up with your forefinger. While holding that pose, push the trigger pin out from frame left (the side the slide stop catch is on). If you've got the thumb-finger thing right, the pin will slide out like butter. If it won't budge, the slide stop is still catching on it.
Here's a look at the author's Thumb-Finger Technique:
This information is presented without warranty of any kind. The author is not your mother. Good luck. Don't lose small parts. Don't shoot yourself. Don't be an idiot. If you can't help being an idiot, don't handle firearms. DO NOT APPLY BUTTER TO FIREARMS, NOT EVEN IF IT'S UNSALTED. The butter thing was a figure of speech.