This is a nice way to download files automatically from a linux web server for web backups for example.
On the Windows machine download pscp and puttygen at http://www.chiark.greenend.org.uk/~sgtatham/putty/download.html
Start puttygen, click generate, randomly move your mouse over blank area to generate public/private key pair.
Save the file private-key as “private-key.ppk”, and public-key file as “public-key″
Upload “public-key″ to ~/.ssh (/root/.ssh/) folder on the linux box. Then run the following commands to convert the key to linux format then import the key into your authorized keys file.
ssh-keygen -i -f ~/.ssh/public-key > ~/.ssh/user-public-key.pub
cat ~/.ssh/user-public-key.pub >> ~/.ssh/authorized_keys
I tried this command first but authorized_keys2 did not work for some reason maybe realated to a depraciated method
cat ~/.ssh/user-public-key.pub >> ~/.ssh/authorized_keys2
Now on the windows box you can SCP without a password as long as you specify the private key file, using this format
pscp.exe -i YOURPRIVATEKEYFILE.ppk email@example.com:/backups/%year%-%month%-%day%/* D:\Websites\backups\latest\