PSD files are layered graphics file extension developed by Adobe for their commercial program which is very popular among designers – Adobe Photoshop. Adobe Photoshop is surely expensive and not everyone has a copy installed onto there system. So, if you have received any PSD file then these are associated with Adobe Photoshop program. You will have a hard time editing any of the psd file without Adobe program.
Anyway if you want to Preview PSD file then here is a nice little addon I found from blogsdna which allows you to have a glimpse of the PSD file in thumbnail view.
Opening Photoshop PSD File
The freeware PSD file viewer not only opens PSD file but also EPS file from your windows explorer (PS+Ai Thumbs). PS Ai thumbs is hosted on Google sites and should be directly downloaded from here. I have checked out the program and it is free from virus. I’ll come up with few more ideas and other freeware psd viewer quite soon 
