[josh3794]

You have to download the omarket app. but if you google freewarepocketpc (all one word) the first hit will take you to a good site for most apps. This is the site that omarket takes you to. Other then that figure out what you want to do and find an app to do that. ppcgeeks has a lot of apps and so does xda developers. If for some reason something says GSM only don't use it. Also the diamond is considered a vga phone. So don't try and put anything marked qvga or wvga on the phone. It won't work.
Is there something specific you are looking for?

Ring tones you can download from pretty much anywhere off the net. You would put the ring tone file into the folder my device > my documents > My ringtones.

One mention on this. There are a few problems with the ring tones in windows mobile (wm). MOst roms can only use .wav music files for ringtones. So whenyou are looking look for wav files or convert the files you want to use. You would have to find a converter to do that and I don't know of one off hand.