Getting the Built-in Flash to Fire on the D70 with Wireless
Prepared 2005-04-02 by Bill Claff

Here's a good example

The top shot is with the built-in flash alone, it's OK.
The bottom shot is with my SB-800 around the corner in SU-4 mode, Manual, 1/32nd power; clearly better!
Both are D70 18-70mm @18mm f/3.5 1/60th ISO200