You need software called poi-loader. http://www8.garmin.com/osx/
This will transfer poi files from your computer to the device via a usb cable. Creating you own poi files is fairly easy. Before taking any trip I always research the area and using google maps I create a poi file tailored for the trip. My garmin is a nuvi.
A poi file is nothing more than longitude, latitude (coordinates) and descriptions, one line per location. I create them as csv files with excel. The trick is getting the coordinates. You can find sites that geocode addresses (provide an address and they return the coordinates). Another option that I use is an option for google maps. If you can find the location you want to mark on a google map, select 'map labs' on the bottom left of google maps and turn on 'LatLng Marker'. Find the location on the map, then right click and select 'drop latlng marker' and you will see the coordinates. Then use the coordinates in the csv file.
The entry in the poi file would look like....
-73.96258,40.70998, Peter Luger
You should also become familiar with www.poi-factory.com
, tons of free poi files are posted there and a community that will help you.
<message edited by kozel on Thu, 05/23/13 9:25 AM>