So you want to start in graphics? There are several ways to start. You'll need imaging editing software, some are free or open source and some are for purchase. I would suggest to try the free ones first to make sure you are interested in graphics before purchasing.
Imaging Editing Software:
Gimp Free
GimpShop A mod to gimp to replicate a photoshop feel.
Adobe Photoshop and Photoshop Elements Photoshop is a robust program with an expensive pricetag. Elements is more affordable for the hobby user.
Corel PaintShop Pro Very robust program with a hobbyist pricetag.
Tutorials:
Gimp TutorialsPhotoshop Online Class (early versions)PaintShopPro TutorialsDon't forget there is practically a video about everything on youtube!
3D Software:
DAZ Studio Free! But beware it's very much addictive and although there is lots of free content...there is alot of commercial products that add up over time!
Poser Not free! Uses the same content (for the most part, there are items that are not transferable between the two prgrams) as DAZ Studio.
There are many more 3D programs available, most are not free or carry a pricetag unattainable for the hobbyist.
The most important item you need is creativity! You are only limited by your imagination!
Please remember that graphics you see on the internet are not free to use unless specifically stated!! It is unethical to grab someone's artwork and display it without permission.
This is just the tip of the iceberg and there is soo much to learn, if you have any questions be sure to post them as I'm sure others will learn from it also.
Happy graphicing! XD