I found this thread on how to write fan mail without sounding like a dork. And while you probably won't hear much personally from, say, Brad Pitt, if you write fan mail to one of your favorite authors, you might hear something back. I've made a few writing friends through fan emails, so never hesitate to tell someone you admire their work.

While it's fine to say that you're a writer, or that hope to achieve what they have done, or something along those lines, you probably don't want to include the first 200 pages of your novel for their perusal. And you probably don't want to ask them how to get an agent. While I have heard urban legends about writers sending back materials with comments on them, I don't believe this actually exists. Keep it brief, keep it complimentary, and maybe include a "I'd love to pick your brain sometime, if youd have time," which could lead to an email or phone conversation. Maybe.

Basically, don't be scary.