I have posted two resources to help you. The first is "a parent's guide to twitter," designed to help you better understand what twitter is all about. I then posted a step-by-step tutorial for creating a twitter account and linking it to your cell phone. Just like Google, Yahoo, Bing, or any online resources you may let your child use, twitter is a powerful and useful tool that is also a window to the wide world, so it's important for parents to understand twitter before setting up an account.
a parent's guide to twitterhttp://www.scribd.com/full/39963470?access_key=key-19v3yn8z30mqma3k2yzf
create your twitter account and link it to your cell phone - Step-by-Step Tutorial