I should be able to do this for you. Zooming in and out would be fine. I can make it jump to certain sizes (IE: 2x, 4x, 0.5x, 0.25x, Etc), as well as add in your locations.
If you have a MySQL database, then I can store the information on where the location is located, otherwise I can use an XML file.
The price depends on how much you're willing to spend. PM or Email me and i'm sure we could come up with an amount that would satisfy both of us.