I lovelovelove Design*Sponge. It's a blog of lovely, pretty things that never fail to inspire. And because the folks over there are dedicated to spreading the pretty around, they do things like make these ooh-worthy bookplate templates so everyone can enjoy them. Click here for full instructions and to download a template. If you can't pick a favorite, download 'em all!
EDIT: The link is fixed - sorry about that!