Littlecoo is correct. These are vector graphics created in Illustrator, Freehand or Corel Draw.
There are two kinds of graphics programs. Draw (Illustrator, Freehand, Corel Draw etc.) and Paint (Photoshop, Painter,
PSP etc.) You can only achieve the clean sharp lines, such as these graphics have, in a drawing program. They can be combined with Photoshop projects and maintain all their crispness and this is true especially in Photoshop CS2 which uses "smart objects and retains all the vector information through output.