Garmin GPS devices can only read POI files formatted as GPX. Other devices such as the TomTom GPS are only compatible with files formatted as OV2. Whether you're converting a POI file so it's compatible with a Garmin GPS, or converting a Garmin POI file so it's compatible with another type of GPS device, there are various online tools and software programs that can help.
Convert a Garmin POI file with POI Editor (see Resources), a free, online conversion tool. This tool converts GPX, OV2, KML, LMX, CSV, ASV, ITN and UPOI files. First, load the POI file into the interface. Select the "Save POI file" tab and enter a new name for the converted file, if you prefer. In the same tab, select the output conversion and download the converted POI to the computer.
Change the format of a POI file with the POI Manager (see Resources). This free online tool will convert CSV, GPI, KML, GPX and OV2 files. To convert a Garmin POI file, upload the file to the POI Manager interface. Then select the edit option. All of the uploaded POI files are displayed. Select an output format besides the "Save As" option and the POI files will be converted to the specified output and will automatically download to your computer.
Reformat Garmin POI files with the PoiEdit software. This software converts Garmin POI files to a variety of formats including OV2 and GPX, and also includes design features so you can create new POI files from scratch. Once converted, the software downloads the POI file directly to your GPS device. This software is free to download and install.