Lets say i create a new document of
800px x 800px and I take the cursor on a particular point in the document. How would I know which pixel this cursor is at this moment?
The Info panel will tell you what position your mouse is at.
To display your info panel go to
Window > Info, or hit F8 on your keyboard.
Also note that it may default to a unit of measurement other than pixels such as centimeters or inches. If this is the case, click on the "+." next to X and Y as highlighted in the picture above, and select Pixels from the drop-down menu.