The ChromeOS application menu has some pretty cool icons for applications — so much so I’ve cheekily popped some of them here for your downloadable convenience. All are 128×128 and would look great in docks and menus for your webapps.
Right click and save as to download.
[GMail, Hotmail/LiveMail, Yahoo! Mail]
Google Apps
[Calendar, Reader, Docs, Youtube, Tasks, Picasa Web, Contacts]
Other
[twitter, facebook, calc, hulu]
Copyright belongs, one would imagine, to Google.