No, it's not pirated. 
This is pretty cool... Adobe, the maker of Photoshop, has released a bunch of their classic software packages for free.
They've put up a page on the Adobe site where you can download full, 100% legal copies of Photoshop, Acrobat, GoLive, Illustrator, and more straight from them, and Adobe even provides a serial number for activation:
http://www.adobe.com/downloads/cs2_downloads/index.html (http://www.adobe.com/downloads/cs2_downloads/index.html)
I don't think these are the very latest versions, but Photoshop CS2 for free? Hell yeah.
Not a scam or spoof, it's legit:
http://www.premiumbeat.com/blog/adobe-cs2-photoshop-illustrator-free/ (http://www.premiumbeat.com/blog/adobe-cs2-photoshop-illustrator-free/)
http://reviews.cnet.com/8301-13727_7-57562515-263/adobe-releases-creative-suite-2-for-free/ (http://reviews.cnet.com/8301-13727_7-57562515-263/adobe-releases-creative-suite-2-for-free/)
http://nofilmschool.com/2013/01/adobe-releases-creative-suite-online-completely-free/ (http://nofilmschool.com/2013/01/adobe-releases-creative-suite-online-completely-free/)
