I have zero experience with OpenGL and a small amount of experience with Objective-C, but I'm fairly decent with C++. What resources should I be looking at to start learning how to use OpenGL within Objective-C? 

I read somewhere at some point that starting out with NSOpenGLView is a good start.
['https://Stackoverflow.com/questions/5384157', 'https://Stackoverflow.com', 'https://Stackoverflow.com/users/657850/']
Honestly, you're probably not going to need to know much Objective-C for dealing with OpenGL, just C. OpenGL is C-based, so you don't need to learn anything new, language-wise, to deal with it. Objective-C knowledge is only really necessary when you plan on using Cocoa to build up your interface. Even then, the language is not hard to pick up if you're coming from a solid C / C++ background.

I highly recommend the book [iPhone 3D Programming](http://oreilly.com/catalog/9780596804831?cmp=il-orm-ofps-iphone3d) that Matt's first resource is based on. Even though you're asking about desktop OpenGL, and this book covers OpenGL ES, much is shared between the two APIs. The book does a great job of starting with simple concepts and fundamentals, and then building to more advanced topics like environment mapping and custom shaders. The author uses C++ as his base language for the book, so you should be familiar with even the most complex code he shows. OpenGL ES is effectively a subset of OpenGL, so almost everything translates across to the desktop.

Within a desktop Cocoa application, you have two ways of presenting OpenGL content: NSOpenGLView and CAOpenGLLayer. The former is an older NSView subclass that you can customize to place your rendering code within. The latter is a Core Animation CALayer that also acts as an OpenGL rendering target, but it give you a little more flexibility in how you can overlay other items on top of the OpenGL content. Getting the display set up for your OpenGL rendering will not take a lot of effort, with most of your time being spent on your OpenGL code.

You might want to pick apart some of Apple's sample applications, such as [GLSL Showpiece](http://developer.apple.com/library/mac/#samplecode/GLSLShowpiece/Introduction/Intro.html#//apple_ref/doc/uid/DTS10003935), [Cocoa OpenGL](http://developer.apple.com/library/mac/#samplecode/CocoaGL/Introduction/Intro.html#//apple_ref/doc/uid/DTS10004501), [GLEssentials](http://developer.apple.com/library/mac/#samplecode/GLEssentials/Introduction/Intro.html#//apple_ref/doc/uid/DTS40010104), and [CubePuzzle](http://developer.apple.com/library/mac/#samplecode/CubePuzzle/Introduction/Intro.html#//apple_ref/doc/uid/DTS10000521), among the other OpenGL examples they have in the developer center.
Given your affinity for C++, [this](http://iphone-3d-programming.labs.oreilly.com/) will probably be the most appealing resource for you. It covers OpenGL ES 1.1 and 2.0, so you'll get all you need to know.

Personally, I really enjoy [this set of tutorials](http://iphonedevelopment.blogspot.com/2009/05/opengl-es-from-ground-up-table-of.html), which avoid C++ and are quite well written. It only covers 1.1, but that may be an easier place to start anyway.