How to separate from Sheets??!!

[DEFECTX9]

hi!  I am working on a new game project and i found some really cool sprites on you're site,  however they come in "Sheets". so how do i separate the Sprites to use them in-engine? Sorry if this is in the wrong place as i really wanted to say my welcome and than ask for some quick help, and also sorry if this is a stupid question, i just have no idea how to separate them  

[Witch]

If you use Photoshop program, then use Rectangular Marquee Tool by pressing M button on keyboard or selecting second icon from above, after that by holding left button of mouse marquee necessary sprite and press CTRL+C button combination to copy your sprite, further make new sheet list by pressing CTRL+N with width and height parameters you needed, then press CTRL+V to paste sprite on your new sheet list, and don't forget to delete background color by using Magic Wand Tool, or pressing W button.