Being a very small Indie iOS developer, I usually have more than one project "in the works" and I will have an idea or I find some really cool sound effect or maybe some new code snipit that I want to use / include in one of my projects. How and where do you track that?
I keep any number of text files in my project that I can quickly reference right from inside Xcode. Here's a very quick "How To"
Step 1
Create your text files using TextEdit (or your favorite editor) and save them in your projects folder (you can even use a sub-folder). In TextEdit just hold {CMD} + {SHIFT} + {T} to switch from RTF to plain text.
Step 2
I create an Xcode group to keep my text files together, it's up to you.
Step 3
Add the file(s) but make to to DE-SELECT your app in the "Add to Targets" checkbox, otherwise you'll get errors about not knowing how to compile a txt file (or something).
Step 4
Revise and update directly inside Xcode.
You can use RTF files too, it's just not as easy to edit the type stuff.
And of course we have a sample project that you can download here.
PS This technique will also work for fonts that you used while making your assets. I learned this the hard way after I reformatted my old iMac and wasted several hours trying to track down a missing font that I used in a PSD file.
Happy Coding