This page offers a collection of helpful resources for the Nikon D3100 like: a downloadable PDF manual, firmware updates and technical support info.
You can download the official Nikon D3100 instruction manual by clicking here. (this PDF manual is provided by Nikon)
If you’d rather download the manual from Nikon’s official website, just go to the D3100 support page located here: support.nikonusa.com
Included Software Downloads
Nikon ViewNX 2 – Visit the Nikon USA Download Page here.
Support Phone Numbers
Nikon USA: 1-800-645-6687
Nikon Canada: 1-877-534-9910
Nikon UK: 0330 123 0932