Traveling companions and carriers in USA?

I will be driving through the east coast in the following months and I need to know of places in the internet where I can coordinate picking companions or items to transport (All Legal) So I can make some money for gas. I used something similar when I moved to VA for my pets. Does anyone knows of groups with similar needs?

Go to craigslist.com and there is a section called 'rideshare' that should be able to help you.