HI Friend,
There are lots of sits but I think www.masterfile.com and www.sxc.hu are very kool sites. in master file u can get small pic for web or other press work and from www.sxc.hu you can get big images if you are desinging big designs for billboards and any other huge projects.

2: DO check this site http://www.webdesign.org, from here you can get lots of help regarding diffrnt desiging softwares like adobe psh, adobe illus, coral draw.