MySQL Database Locking - needed?

Hi The company I work for has recently developed a Car Dealer type site, which acts as a large on-line used car yard. Currently the MySQL database holding the cars is added too / edited / deleted by one person employed for the job - but we hope to expand to allow the Dealers themselves admin rights to their on-line cars. I have begun development of a Dealer Admin area - but have a couple of questions regarding this: 1) Would any sort of Table Locking be needed for this - for example if two people were trying to update the same car, at the same time etc etc.. 2) If yes, is there any on-line documentation on this? 3) What other problems could arise if this was implemented? Thanks all Tom Peck