I used the POI Loader that Mike (264SRinPA) linked to.
Plus I've downloaded a lot of the POI files from the POI Factory.
The POI Loader works great.
I've used it to download custom POIs to our Garmin StreetPilot 230 and nuvi 255.
You can also create your own custom POI files, they're just csv files, and then load them on to your Garmin using the POI Loader.
Download & install the POI Loader from POI Factory web site, using the link that Mike included in his post.
The only other thing you need is a USB cable to connect your Gramin to your PC. A USB cable came with our StreetPilot 230, which also works with our nuvi 255.
When you use the POI Loader to load custom POIs onto your Garmin nuvi 255, it will place them under the "Extra" POI category.
I don't know if there's a way to control where the custom POIs are loaded.
Mary & Tom (aka Hutch)
2015 Jayco Eagle Premier 361REQS
2014 GMC Sierra 3500HD 4x4 CC D/A
Sunlines: 2005 Solaris T-280SR; 1999 Solaris T-2670; 1998 Saturn T-24A