Here are a couple great resources for getting going in these industries.
The
Volition.com Forums are a highly active group of forums about these opportunities and more.
Contractors provide feedback on virtually every company in these industries. It's a great community.
Instead of registering with all of the various companies out there only to find out they don't work in your area, you can use the following sites to see who might have work where you live.
Visit the
National Association for Retail Marketing Services(NARMS) job bank and search for merchandising openings in your city, state, or country.
Register with
JobSlinger.com and search for opportunities in your immediate area.
As we go, I'll be adding some direct links to companies that seem to be highly rated among their contractors.
Good luck.