Either Photoshop or Illustrator. There are really no other alternatives. And It's all in personal preference which program you use.
Photoshop uses and creates raster images, or bitmaps. In other words you can only blow a picture or design up as much as the pixels (picture cells) allow. You create and edit designs and photo's using pixels
Illustrator is vector imaging. Instead of creating an image using pixels you use vector lines. Basically it creates lines using mathematical formulas. This way you can blow your design up as big as you want and still have all the detail. However, the interfaces are slightly different and personally I havn't delved too deep into vector imaging just yet, but I do know some info on it. Also you cannot edit real pictures in Illustrator.
What kind of tutorials are you looking for? I may not be "pro" with photoshop, but I consider myself proficient with it and can give you some tips/pointers.