List of business in a specif area

when a user clicks on a link that gives a map w/a the vendors or business in a specific area, like “click here for all the shops selling ice cream brand acme in your state”
Can anyone point me to a tutorial or info on how to get it done.
I know you can use the google api to show the user the map to your own locations.
But I’d think to show all the business you want in a map you’d have to code in the lists of course?
Has anyone done this and can provide advice on how to do it?