Helping a Timid Puppy with Submissive Peeing

Here's a tip from Dogster.com:

Submissive peeing is a sign of apprehension, fear and excitement all in one. The first step for helping your puppy get over it is to ignore her when you first get home. After you have ignored your dog on your arrival, you can reach out to pat her by giving a scratch to her chest, but don't reach over her head to pat her head, since that is a threatening move to a dog who is already timid. Keep the greeting calm, with a quiet, low key voice.