This method is a lot of work. Use Google Earth, type in each address, and it will show you the location on a satellite photo, along with the Lat-Lon. You can then enter the Lat-Lon into a file, and later download it into your GPS.
I am sure there are many other methods that would be a lot easier, and I am sure someone else on this forum will chime in.
FYI: Here is a sample POI for Cracker Barrels:
-81.05369,37.36135,"Cracker Barrel-294 Meadowfield Lane"
-81.0561,36.9488,"Cracker Barrel-160 Lithia Rd"