I don't think I've mentioned the science program we decided to use this year. We chose it because it was free. We figured first grade life science was a pretty easy subject to cover without a curriculum, so we didn't want to pay a fortune. We're using Scott McQuery's Classic Science: Elementary Life Science and we're enjoying it so much that we're pretty sure we'll fork over the $50 for the next book.
The unit that we're about to begin covers the biomes of the world. I found some nice notebooking pages for biomes at the Yahoo Group Notebooking2Learn.
Exploring Nature has some nice illustrations of the biomes of the world that I'm thinking of printing onto cardstock. Plus a pdf file habitats of the world activity.