I'm ready to add some color to my site, and I need a huge collection of flgs of the world. Must be in 20x10 pixel
size or I can resize it.

Any hint?

try this link (http://www.theodora.com/flags/flags.html)... they've got tons of flags. Not sure if they have the right size, but its worth a look. :)

Try this one too

http://www.flags.net

Wing.

That's easy. There are a number of graphics sites with flag collections. At least one even has them all animated. You can do a quick search on Yahoo. The sites already referenced might fill your needs as well.