mmm... that's a lot of questions... but here we go:
1. To make wallpapers you have to use some image editing program. Most people use Photoshop, but you can also use Paint Shop Pro or GIMP.
2. You don't need to draw or scan to make wallpapers. You can, if you want to use your own designs and/or images you have in paper, but it is not necessary. Most wallpapers are created using other images and composing them and adding effects/backgrounds/etc..
3. Nope. no moneys... People upload, contribute and share because they love anime and want others to enjoy it too. The only one who could make money is me, since it is my site and the revenue from ads is in my name, but it barely covers the costs of the server... If you add the headaches of moving servers and all the coding involved... I'm not going to go there, because I wouldn't continue with site if I was thinking about the money... hehehehe. Maybe if some day we have thousands of users, or we get more clicks on the ads I can make a little to buy some games/anime with it, but... it is a good thing I have a real full time job, otherwise i would be homeless!
Organize your anime! => Anime List Builder v3.0
it's a new high quality anime try it 
and ahm well that's all for now LOL
