Just downloaded the developer previews. I decided to give you a pack including all the new icons
All the files are in 1024x1024 px, PNG and/or ICNS.About specific icons :
Finder & Trash
A PDF file is included in the set, with all the instructions in order to change theses icons.Calendar
The resources & the instructions for the calendar icon are available here
If you want a Mavericks-sized icon, take a look here
Apple didn't release iTunes icon in the first DP. You can download a remplacement icon from Ziggy19
UPDATE 9 : Added the new icons of the 3rd DP.
UPDATE 8 : Added the new icons of the DP2.
UPDATE 7 : Calendar icon is now working properly.
UPDATE 6 : Updated Calendar icon, to make it working on Mavericks and Mountain Lion.
UPDATE 5 : Added informations about specific icons in the description
UPDATE 4 : Added Instructions in the .zip file
UPDATE 3 : If you want an iTunes icon, take a look at this one : bit.ly/1jOXNOi
UPDATE 2 : Added Finder Icon
UPDATE 1 : As you can see on the screenshot, iTunes icon is still the old one. I'll add the new icon when it will be released ! My website