Stock Photos
http://www.sxc.hu/index.phtml
http://www.freestockphotos.com/FreeGeneral.html
http://www.copyright-free-pictures.org.uk/
http://commons.wikimedia.org/wiki/Category:Dogs
http://www.flickr.com/search/advanced/ (creative commons only)
http://search.deviantart.com/?q=stock%20photos+in:resources/stockart/animals§ion=browse&qh=boost:popular%20age_sigma:24h%20age_scale:5
Brushes
http://www.easyelements.com
http://www.brusheezy.com/
http://getbrushes.com/
http://myphotoshopbrushes.com/brushes
http://www.brownbaron.com/blog/2007/10/04/375-free-photoshop-brushes/
Fonts
http://www.dafont.com/
http://www.urbanfonts.com/