What is the best way to build an open source database?

I would like to build a database of all vehicles and the related maintenance information (i.e Oil Weight, Quantity, Tire Pressure, Windshield wipers etc). Currently this information is fragmented or just not put on line in an open way. Once collection began I would want to import into a DB and then be able to distribute freely.

Is there a process (site or group) that I can start gathering this information in a reliable and verifiable way?

Is there any issues that I should watch out for?