How the get the 512x512 icon for any iPhone app.

gistfile1.txt

How the get the 512x512 icon for an app.

Look for this app on the itunes.apple.com website (Google is your friend)

For example, this excellent app.

http://itunes.apple.com/au/app/bancomap/id309009025?mt=8

Look for the URL of the icon in the page (it's a 175x175 picture).
I use Safari, so right click on the icon and choose "Inspect Element"

http://a2.mzstatic.com/us/r1000/105/Purple/v4/c6/56/51/c65651fc-255d-6fde-3204-65759263f723/mza_4948490935921782655.175x175-75.jpg

Replace 175x175 by 512x512 in the URL.

http://a2.mzstatic.com/us/r1000/105/Purple/v4/c6/56/51/c65651fc-255d-6fde-3204-65759263f723/mza_4948490935921782655.512x512-75.jpg

Voila.