If you instead input username@free.kindle.com, it sends it to your email so you can download it and put it on your Kindle.
Wifi is always free. (source: http://www.amazon.com/gp/help/customer/display.html/ref=hp_l...)
A genuine question: how does Amazon check the autenticity of received emails? I mean: what if I forge the email address you use to send articles?
I have never had a problem with Kindle spam.
You can just go clickhappy on your pages, have them converted to mobi format, and sent to your kindle every day/week/month etc.
It runs the epub through calibre convert, because the sony reader has issues sometimes with the instapaper epub file - the conversion fixes it (something to do with chapters over a certain length).
Through the evening, I instapaper save anything interesting to read, then just run this script each day before I leave the house.
This is the particularly rare-groovy batch code if anyone's interested.
@echo off
echo. Echo Creating cookie... echo. curl -c cookies.txt -d "username=youremail&password=yourpass" http://www.instapaper.com/user/login > temp.txt
echo. echo. echo Downloading epub... echo. curl -b cookies.txt -o C:\Users\Nick\Development\scripts\instapaperbad.epub http://www.instapaper.com/epub
echo. echo. echo Converting epub... echo. "C:\Program Files (x86)\Calibre2\ebook-convert.exe" C:\Users\Nick\Development\scripts\instapaperbad.epub C:\Users\Nick\Development\scripts\instapaper.epub
echo. echo. echo Copying file to device... echo. copy /Y C:\Users\Nick\Development\scripts\instapaper.epub F:\database\media\books
rem Cleanup. technically we can keep cookies and re-use. del temp.txt del C:\Users\Nick\Development\scripts\instapaperbad.epub del cookies.txt