No, there are Windows and Mac versions but they are separate.
Photoshop CS5
Maybe CS3? It is version of Photoshop
Adobe Photoshop CS5
Adobe Photoshop CS6
Yes. Photoshop can save a number of formats that can be used on almost any platform.Tiff, JPG, gif, PDF are all platform independent and can be used on almost anythingPhotoshops native .psd format can be opened by Photoshop on Mac or PCOf course, if you are using version CS3 on a Mac and version 6 on hte PC, you will have problems opening the newer version file on the older version software. But that is just the nature of software versioning and has nothing to do with platform.You do have to purchase a different version of photoshop for whatever platform you are using. 1 Copy will not work on both. (Just in case that was the real reason for the question)In More Simple TermsThere are separate versions of the software, but it works on both platforms, and the files are compatible.
The most current version of Adobe Photoshop can be found at www.adobe.com
Adobe photoshop CS5 (extended)
You can go to www.adobe.com/downloads and get a trial version of Adobe Photoshop CS4 for free.
no. you have to get the mac version of photoshop
Yes you can download photoshop trial versions
Well Photoshop Elements is basically Photoshop, but that everything is already ready there. it's like easy version of Photoshop.
Adobe Premier Pro is used by customers that require a professional video editing software. This is a multi platform software that comes with after effect, photoshop and many other features.