Like frenchfry said you can still develop for Dx7 with the Dx8 or 9 SDK. You'll want to add the following line(s) to your source:
From the way your original question read it looks like you asking for the documentation and that you just want the help file/examples for Dx7 specific things, like Ddraw. If that's the case, I uploaded it to my site for you to download it here (5 MBs).
#define DIRECTDRAW_VERSION 0x0700
#define DIRECTINPUT_VERSION 0x0700
//etc, etc for each component you use