Well I've got a question(s): How can I check if OpenGL 2.0 is installed on PC? And if not from where can I download it? It's a bit confusing because it's released for about 4-5 months. And I can't find it anywhere! Maybe I'm looking in the wrong places.

OpenGL 2.0 is just another bunch of extentions thus there is not really that mutch you could download.
go here if you want the new header file
http://oss.sgi.com/projects/ogl-sample/registry/
other than that you should allso go and download your latest graphics card drivers.
allthough it doesn't officially say that it supports openGL 2.0, most of the newest drivers does support the functionality.
I guess it will take another 2-3 months before they say that it supports openGL 2.0, i know that nvidia won't release another one of their forceware drivers before they have coded the EXT_framebuffer_object extention, and that will take that long at least.
I don't know about ATI though.

That actually leads to another question: is there any real difference between the OpenGL 1.x and 2.0 API's? I understand that much of the technology was already available, but has the way of accessing that technology changed much?

>How can I check if OpenGL 2.0 is installed on PC?

Check if glGetString(GL_VERSION) returns 2.0.

>And if not from where can I download it?

Just update drivers.

>It's a bit confusing because it's released for about 4-5 m

The specification was released. There are no implementations yet.

>OpenGL 2.0 is just another bunch of extentions

No. OpenGL 2.0 promotes some extensions to core features. The same fetures can be used with extensions without OpenGL 2.0.

> but has the way of accessing that technology changed much?

No. New symbols are defined in glext.h and entrypoints to new functions are loaded with wglGetProcAddress() (for extensions AND core features).
Easier way is to use extension loading library like GLEW ( which loads core features as well ).

Double post from the OpenGL forum, don't bother replying.

Seriously, why do people do this anyways?