Here are some sites worth checking out.  First up is a blog focusing strictly on scientific news breaks. ScienceDaily has much of the same thing but in more of an uncondensed newspaper format.  Check out some very cool bugs in the entophiles, or get specific and look at insects from a single country, like Thailand.  For you water-loving folks, visit the Aquarium of the Pacific and browse the Animal Database.  Learn to distinguish a butterflyfish from a mackerel or a goby, or sit back and look at the best photos of the month from FishBase.  There is a site out there for you, whether you prefer amphibians, or reptiles, or if you'd like to click through the whole animal kingdom (but be aware of the evolutionary slant).
Two other sites I like are Nine Planets--"A multimedia tour of the solar system"--and another site called Naturesongs, where you can play clips of bird calls, bee buzzings, or--if you're interested--the sound of a striped skunk.

Please note: The "Recommended Sites" page has been updated.