Beader's block? Never again! Mostly my problem isnt to find something to bead but to choose between the abundance of ideas I have. So when searching for images its important to have a theme in mind to help focusing.
If searching for video game sprites there are several sites with good archives; the most known is http://www.spriters-resource.com/ where there are regular updates. In my links list you can find more sprite sites.
I also like to see finished projects - those I find on flikr, deviantart and http://www.pixelgasm-forum.com/. Pixelgasm is a great place for inspiration, tutorials, supply advice etc.
If youre looking for something to do with/for your kids PerlerBeads site has plenty of good projects - I especially like the 3D ones. Hama's site is still rather new but has a few patterns.
If you like to make photos/images into beads (using perler or photo pearls) Ive found a lot of interesting images on deviantart.
And remember when searching that cross stitch patterns can be beaded very easily too!! Besides sprites patterns Ive been inspired by the Prairie Schooler Patterns.
Do you have a good site where you find inspiration? Id love to put it up here then :)