The American Red Cross has a very informative article on how to construct your own home made first aid kit. Having a first aid kit available at home, in the car, or for any other activity, is very important.
You can read more on their website:

American Red Cross First Aid Kit

FEMA is the goverment agency dedicated to supporting citizens and first responders in preparing for hazards. They suggest many ways and items you can easily obtain to help prepare yourself and your family for potential disasters including first aid and emergency kits.
You can read more on their website:

Federal Emergency Management Association

The National Safety Council strives to save lives and prevent injuries in the home, workplace, communities, and roads. The informational website contains many helpful tips and practices plus products and training to help you, your family, and your workplace become safer environments.
You can read more on their website:

National Safety Council

The National Highway Traffic Safety Adminstration was established to carry out highway and driver safety programs. They explain many ways to prevent accidents and how to reduce the risk of injury before or after one.
You can read more on their website:

National Highway Traffic Safety Administration

Edmunds, a website devoted to new and used car buyers, has a very informative article on how to create your own roadside emergency kit. Being able to make your own repairs or wait in safety and comfort for help to arrive is very important.
You can read more on their website:

Edmunds Roadside Emergency Kit

LIVESTRONG, part of the Lance Armstrong foundation, has an article by James Patterson about bicycle safety. The article explains bicycle safety basics as well as going over proper safety equipment including carrying a first aid kit.
You can read more on their website:

LIVESTRONG