I tried the search "send to kindle" in this forum, and I only found random mentions of Amazon's
Send to Kindle. It does merit a special mention, as I find it extremely useful.
http://www.amazon.com/gp/feature.html/?docId=1000719931
If you are using Calibre then you can click on
Click to open and you are immediately in the folder containing the file. A rightclick on the file and you can send it to Amazon.