As this topic has come up a few times, here is how I use my Oregon for Waymarking. These steps should also work for the Colorado and the Dakota as well, but I have not tested these devices.
You must be a "Premium Member" of Groundspeak to use these features. Go to Premium Membership for more details, although the content there is heavily directed towards Geocaching.com
Start by creating some search locations, preferably near your home. You can do this from the "Waymark" tab and then near the top you will see the words "additional search options". Click that and you can select "my home" (if entered into your profile) or make new ones. Another option is to search by Postal/Zip Code, Address, whatever.. the point is to get a list of Waymarks on the screen.
At the bottom of the screen, it should look much like this except for the red marked up stuff.
So click the "Check All" box then click GPX Lite File. This will give you a file of 25 Waymarks. Save this file into a location that you will remember. It will be called "waymark.gpx"
*** If you want to see the descriptions, skip down to the header "USING GSAK", for basic views continue here
I would recommend downloading matching icons for your GPS. You can get them here in a zip file. Once you unzip them, put them in the same directory as the waymark.gpx file
Next you will need a program from Garmin called POI Loader. It is a free download and you can get it here.
So at this point you should have downloaded a set of 25 Waymarks in one .GPX file called waymarks.gpx, have a matching .BMP called waymarks.bmp and installed POI Loader. Plug in your GPS, run POI Loader and it will step you through installing the POIs into your device. They will show up in a new option, likely called "Extras" just like other features already do.
When you want to go visit a waymark, click on Waypoints and the new Extras will be in the list.
What follows is for people with GSAK
*** USING GSAK
Instead of using POI Loader, if you have GSAK then you can transfer the entire "short" description to your unit and make it seem just like a Geocache. Here's how to do it. First you will need to get GSAK, which in NOT free but you can try it for 21 days (I think) and you can get it here
Open GSAK and then use it to open to the recently downloaded waymarks.gpx file that you just downloaded.
Click "DATABASE" in the GSAK top bar and choose "Global Replace". Change the cache type to Virtual Cache. Next click GPS > SEND WAYPOINTS to transfer the database to your GPS. Be sure to give it a name like "Waymarks.gpx" so it doesn't overwrite any existing files. When you next turn on your GPS you should see some ghost icons on your map screen. The GPS will treat these Waymarks exactly like Geocaches.
BQ