Uploading routes into Garmin 500

Am I able to make a route, then upload it or do I have to already have ridden the route for it to be uploaded?
And I assume that it all happens in Garmin Connect? Or are there other sites out there that can be uploaded into the Garmin?

Thanks.

I used this method for my 705. It should work for the 500.

http://the-yosts.com/googlemap_cuesheet.html