The first two I made myself in Microsoft Word.

Dot logo: simple! 3x3 dot array might work for 16x16 icon

Red oval: simple. Web site mockeup is here.

The following are the result of a collaboration of me and Reb. The 'Earth in a cage' suggests both a global network of computers, and an atom (i.e., science). The original icon came from Cryo64:
Pearl, red gradient

Pearl, blue gradient

Earth, lowercase, blue

Earth, lower case, blue, no shadow


Earth, lowercase, copper, large cage

Earth, uppercase, copper, large cage

Earth, uppercase, separate earth with small cage (to be replaced with large cage)

Earth, uppercase, copper, small cage

Copper text (to be put below a copper logo)

Earth and medium cage only (could use as a 32x32 icon)

Black background (for screensaver):