Today, I'd like to draw your attention to several websites I've come across recently and found to be inspiring and/or useful in my first year of teaching. I hope they are able to help you too!
Under The Microscope is a site dedicated to women in science, complete with stories for and by female scientists and resources for budding scientists to get them inspired. There should be more stuff like this out there!
Howard Hughes Medical Institute has free science resources for educators. Most of them are PDF downloads of books or DVDs that you can have shipped, totally for free, to your home or school. They deal with genetics, medicine, evolution and more - the perfect supplement for any biology class, though I even ordered some and may use them in Earth Science.
I also highly recommend that science teachers join the SUNY Oneota mailing list. It was through this list that I discovered these two sites, along with many others. It is also a great way to connect with other teachers in your subject area around the country. They have lists specific to several branches of science, including Earth Science, Biology, Chemistry, middles school science and elementary school science.
I hope these websites help you as you lesson plan for second semester. For additional resources, see my Science Resources page.